That's really interesting. I'd never seen naming as a means to challenge yourself to writing characters. It's nice though and you're right, never heard Rhet before until now, haha.
Honestly I have always been very picky with my character’s names since not only I want them to fit the story but also to be sort of unique. But for the maiden and the prince, I just went with the first ones that I liked and fitted the characters.
Zielle means heavenly, and I think it suits her perfectly given her appearance. Light blue hair with purple strands, pale skin and pink eyes. For the male lead I decided to name him Ambrose which means inmortal and given the background of his past life and his appearance I guess it suits him,
Simon
Because it's a very generic white boy name and apparantly there are a bunch of other BL novels that also have a Simon as the main character. 
Jamie.
(History moment) Back in the 60s and 70s when it began to be ardently clear that superhero comics were here to stay and not going to disappear into obscurity, like Buck Rogers, a lot of creators were creating female "equivalents" of their titular male heroes to create superhero "families". This is when heroes like Batgirl/woman and Supergirl/woman showed up. Wonderwoman and later Vixen (who was also released same time as Black Panther) were the only female heroes with comic strips of their own who weren't linked directly to their male equivalents.
There was a show that came out during this period that had a supersoldier named Steve. They decided that Steve needed more backstory so they wrote in his love interest, Jaime/Jamie. Jamie suffers a terrible fall that should have killed her and she ends up getting the same powers as Steve. Jamie became so popular that after her death (she was only supposed to be a two-episode arch) they bring her back to life.
Jamie became the first female superhero (with the notable exception of Wonder Woman) to have her own TV show completely independent of her Steve. I named my MC after her to honor her.
Ooh fun prompt but also I have seven main characters BUT I will keep it short! Disclaimer, a lot of these names were chosen on a whim/I liked them when I first conceived the characters but over time they kinda grew into their names so...here we go!
Amethyst Nightingale - The Nightingale family is a noble family, aka they're known to breed incredibly strong magic users. Members of this family are named after minerals/gems because the Nightingales are specifically best known for their control over earth manipulation and construction
Ryn Atlas - Ryn was a name based on the existing japanese name Rin but I added a y to feel cool or something idk lol but it stuck. Atlas because the mythology of Atlas is the man who held up the sky and for story reasons...I'll just say Wink
Harrison Adams - I was thinking about Harrison Ford the actor when I was coming up with this character and due to their gruff personalities I decided to lean into it. Adams cause it has a nice ring to it
Qing Lo - The surname is a nod to my aunt whom I love very dearly. Qing because I've always liked the sound of it, plus how many Q names do you come across?
Perry Lenekov - Perry because...Phineas and Ferb...yes yes but honestly its not the only reference. Lenekov cause it rolls off the tongue for me
James Davis - I've always liked the name James and Davis is reference to an old friend of mine...but it's also a very generic white dude name and honestly? Go Off King, lean into it
Pablo Russo - Yeah you're gonna laugh but I named him after the penguin from the Backyardigans. I don't care. I love him. Russo cause I like it?
Anyways I feel like I got off track with this prompt lol
Full name Sun Chi Liang:
Sun: the surname that was gven to his grandparent from his master.
Chi:Younger energy
Liang: to connect.
Fiammetta: in italian it means small flame, it's a recall to her ability.
Baul (pronounced Ball)
Simple, its an ancient name from the bronze age and I can use it as a play on the title of the book, Little Ball of Hate.
Amelie LeRouge
Amelie's first name comes from the film "Amelie", as her haircut was inspired by that of the main character's. Her surname means "the red", and is a nod to Red Riding Hood- the young girl meets the wolves, but this time they fear her.
Rachel Mirowitz
Rachel's first name comes from the poetess Rachel, and also from the figure from the Torah/ Old Testament. Her surname is from a list I found of Czech Jewish surnames from the 15th century.
The protagonist of my fantasy novel is the elf Sherr’Yand’Rull, who everyone calls Sherry for short. I devised the naming system for all elves that way, their first name, then their family name, then their house name. Her undead partner is called Mort’Eand’Thril, but everyone calls him Mort, as most elves have gotten casual. The idea for their names came to be from watching Frasier (which I love) and how the brothers would always drink Sherry or Port (and yes I was gonna call him Port at first lol)
The Protagonist in my comic is Roland. Named after a historical general under Charlemagne, and after his death legends grew around Roland far greater than his historical actions. Picked it cause I thought it was a suitably heroic name.
The other main character in the story is Zyphella, which as far as I know never existed before as a name. I just wanted to try making a made up fantasy sounding name.
My protagonist's full name is Lester Haydar (which was the easiest to choose) I really liked the names of the other three characters who are relevant to the story, although I was a bit hesitant at first: Victor, his twin Bexamin Dautt (being the Galician version of Benjamin) and Marcel Witsel
All the characters' last names are in Spanish and not that common, except maybe Dautt.
I chose them in a curious way, by chance I saw the surnames from a book of sporting events from the 70s and the names from another from the 50s. I selected the ones I liked the most and here they are.
I don't know why, but it happened that way. I didn't even look them up on the internet. 
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My current character names are Yoshiko, Kuro and Kai. I'll stick to those since other characters haven't been introduced yet. I started Nocturne 21 when I was a dumb angsty kid, almost 20 years ago and pulled random names off of anime credits. They've been changed or altered since, because a lot of them didn't make sense.
Kuro's name was originally a longer version of a name I made up that doesn't actually exist in Japan. When I got to the point in my story when I was actually putting thought into it and doing research, I shortened his name to Kuro. In reality the name "Kuro" isn't conventionally used by itself for a name, but it's popular enough in anime that it's not really an issue. There's not a ton of Kanji used for Kuro as a name, but I found one that means "expert" and I liked that for him.
Yoshiko was originally Yoshiro, but Yoshiro is typically a boy's name, which I didn't realize until like 11 years into my story. So that got changed. Yoshiko is currently spelled with the Kanji for "fragrant child" but I might change my mind on that because I'm indecisive, lol.
My MC is "Kai" which is not his real name. It's the name his new family gives him since he can't remember his real name. His name was very difficult to come with and I only came up with it a few months ago. Again, I've been working on this story for 19 years and It's really hard to just give him a new name when I've been calling him something else for two decades. I ended up liking Kai because it has different meanings in several different languages. What sealed it though was there's a character in The Snow Queen named Kai (might have a different pronounciation though) and the character is a young boy who loses who he is when infected by a demonic mirror shard. Since my character loses his identity and since there is a very heavy theme of glass in my story, it kind of seemed perfect. Also Kai's first action when he wakes up is to break a mirror which ended up being a happy coincidence.
All my character names have deep meaning behind them while others are used in a form of satire, like Sebastian for a butler.
I would share them but I haven't published my novel (still preparing all I need for promotion and quality of my work). Now some names have greek origin, others latin, egyptian, indian, etc. I like hiding things in plain sight. Even the middle names and last names have a meaning. I don't want to spoil it but when I build a fan base I will slowly reveal stuff and make events of trying to find easter eggs.
I also hide easter eggs in my covers so when a readers goes back and sees it they notice new details.
Would love to share their names but probably once I release my novel to not spoil anything. 
I can probably share the first name for now. One is Violet and the other is Alexandria. They will both be the MC's of my work. And both have deep meanings behind their names. Violet is mainly because I love the name and if I ever have a daughter I would name her so. In a sense this character is my daughter. Now Alexandria her name has to do with the origin of the name and what it stands for. Telling you a lot of the character.
The MCs names are
Owen & Evan Moriarty (brothers)
The brothers ancestry includes English and Irish so started from there:
Their surname Moriarty has Irish origin, and means 'navigator' or 'sea worthy'. They come from a seaside, gloomy New-England inspired town and navigate the story so the meanings are a perfect fit. It also has that gothic appeal sort of like Mortician/Morticia etc.
Both Owen and Evan come from Irish/ Welsh/ Scottish origins and mean "young warrior".
Both are young boys who master newfound abilities and fight for survival.
Owen's nickname is Owz and Evan is usually called Ev
for Elf Noir I chose Tolkienesque elven-sounding names for the main elven characters. Arq is short for Arquë, a variation of the French word which has an accent rather than an umlaut. It has several meanings, including arched and bowlegged, but the meaning which I feel fits Arq best is 'Bent'.
In some cases I make my characters' names randomly based on "having a right sound," they are from various fictional cultures so that I have to make names from each culture have coherency and pattern in it. In the other hand, there are names derived from real life words or adapted from real life names.
Sometimes I do things like "Sakhar Mikhas" that sounds like a pun.
Usually my characters names come from people I actually know. For example my character Pujita from Cracking Eggs was named after my friend Pujita in high school. I wanted an Indian character as tribute to one of my good friends.
Eric Stanford was kind of taken from my friend Eric but also wasn’t really. I just happen to like the name Eric. It’s a nice simple name.
Usually with my characters I don’t go for anything too complicated because then I can’t remember them. I feel like simple names tend to resonate and be more memorable.
Names like Nova, Jon, Roy, Elsie, Charles, Knox, Jack, etc. they are simple names but I remember non complex names. Double points if the characters mean something to me or I remember them.