Huh. Interesting. You know, I find a relative lack of resources myself on the subject of the creative process myself. Probably due to both not having gone to extreme depths to find quality material myself, and also because creativity isn't a fundamentally well understood field in its own right. Probably the latest research on actual practical machine learning and creativity as a rigorously defined computational process only came out last year, and I only know that because I read an article that said machine creativity studies basically had their first breakthrough in 2018.
Having said that, I have my own theories about creativity. More creative people tend to be willing to entertain "what if" scenarios past the point which most people would have bothered. They do tend to daydream more, and there does seem to be an association with, in fact, "associative memory" and making connections. Highly creative people tend to be interested in lots of stuff, and like to make connections between things that seem very distant. Creativity is a cumulative process, as opposed to an ordered one.
So, for example, typically linear thought involves organizing a sequential series of steps and then following through these steps. Point A, to B, to C, to Finished. Creative thought leaves out the Finish line, and tends to re-evaluate what actions or pathways to take after traversing each point. So, after point A, there are seven possibilities. Pick one. There's now 7 more possibilities. Oh! And there's no final destination at all!
lol. The earliest seeds for my constructed world, The Kolldrunn, which is the setting of my webcomic, was planted because I wanted to make a nation that would call itself, "The Kettle State", believe it or not. Over the years, I slowly added onto that. "The Kettle State" became "Kedelstadt", and since "Stadt" was a german postfix, I decided on creating a Germanic conlang called "Teune". But then I added "Russtadt" and "Slavstadt", and I noticed that Russ and Slav were both Slavic terms, so I decided to add slavic influences to the language. And since I couldn't come up with any more "--Stadts", I ended up saying that these three nations shared a common heritage and were cultural cousins. But then that lead me to come up with a nation that wasn't, and that ended up being the nation of "Vadjyara".
But I noticed that I took the name "Vadjyara" directly from the name of a race of Blue humanoids called "Vadjyarakoi" (Most DEFINITELY because of laziness, I assure you! :D), and so I decided that the Vadjyaran culture was actually due to serious cultural mixing between humans and Vadjyarakoi, and because the Vadjyarakoi were blue, I decided that their homeland, the "Polniegseule Basin" had a unique species of pine that produce blue pollen and pine needles, and bathed everything in ever shifting shades of blue. And then I decided why not make the place full of rivers and fog and humidity, and the epic and quite and strange and surreal environment then directly contributed to the style of magic that the Vadjyarakoi use...
and so on and so forth. Being creative is a lot like having fun getting lost. You look around, you make connections between what you have to something that isn't there yet. And then, having made the connection, you restructure other parts of your work to make it fit, and then, once you've done that, you've successfully assimilated a new pillar within your creation, and so you repeat the process. And all throughout this tangled web of cobbling together pots and stitching together parts of the long-dead cadavers from other works, you eventually end up with an organic whole that is seamless, and seems so genuinely creative that other people can't even begin to fathom how you came up with it.
I wish I could point to some in-depth resource or some academic literature for you, @Fennecky, but all of this is really my own thoughts on the topic. I hope you do find what you're looking for, though!