I just need to say that I freakin' LOVE your personality descriptors for Rooftop Bookshop xD
As for me, after watching a lot of other webcomic artists struggle with having cast pages that they'd always feel the need to update or completely redraw as their art evolved, I decided I would make it as easy as possible to use art cropped from pages, so I can just crop a new panel every time a piece of art starts looking too old. xD So my cast info isn't in an "info sheet" in the same way, but I do have all that stuff on my cast page, like this!
(the rest of them are over here : D )
For me, other than picking out songs and birthdays and other silly vital statistics, I just add a sentence or two that give an glimpse of the character and what they're like and what their deal is in the story. So for example, Xira's bio implies that he's nervously hiding the fact that he can read minds. That's TEEECHNICALLY spoilers if you're not caught up, but I'm okay with that -- it's a pretty early impression of the character, and it's also the sort of thing that, if I were a potential reader, might make me think "oh that character sounds neat, I'm gonna read this story."
Basically I guess I think of the character bio like a pitch for that character -- a piece of what makes them interesting, without explaining them too much.
But I'm also updating the cast page as I go, so you'll never see a character that's yet to be introduced. If I were gonna show the ENTIRE cast page up front, I'd probably just give first impressions; like, Xira would just be described as helpful and "strangely perceptive" to sort of suggest his issues without revealing them early to everyone.