So, I've been doing a bit of thinking lately, and I think there will be a slight change of plans. Or at least a slight change in my approach to getting this finished.
I've decided that once I finish with procedural creature generation, most of the rest of worldgen will go on hold. There is already sufficient data for each world for me to start on gameplay elements, and as much as the OCD perfectionist in me wants to finish worldgen completely before I start working on gameplay, it doesn't seem practical if I want to turn this into a serious project with sustained community interest. No matter how neat a game engine may be, without a way to interact with it, it just won't generate the momentum and interest necessary to propel it forward (at least, this is what I'm beginning to believe).
So, procedural creatures will be the last major hurdle before I begin working on gameplay itself. I'll still do a final tech demo release with the worldgen and World Atlas features that are currently functioning, and then I'll begin work on getting an actual game together. The first release or two are likely to be basic and probably somewhat buggy, with the primary draw begin an open, very large (and hopefully interestingly variated) world to wander around in and interact with to some degree. I doubt towns will be coded as of yet because the level of detail that civilizations will require in this game will necessitate me doing a lot of extra work on them before I start to implement them in-game (especially with some of the goals I have in mind like culture-differentiated architectural styles and whatnot).
But, anyhow, the good news is that after I get some gameplay elements in, I can work on worldgen and gameplay at the same time, since changes in gameplay will depend largely on adding new code to worldgen and then working it into the game in an interactive manner.
Wish me luck!