Welcome to the Guild! That's an ambitious project. I never played Spelljammer but always thought it looked like a fun setting. Some of what you want (mapping Earth-like worlds and locations) is right here. A few of the odder things you mentioned can be cobbled together from the techniques you'll learn along the way. A couple of them you might have to pioneer on your own. It's a worthy project, though, and I'd be happy to help out with advice if I can. I've been working on a ship battlemap for a bit now (link) and have maybe a little experience that can help with deckplans. So. Yeah. Pick something and start working on a map and then post a work-in-progress in the appropriate forum.
M

NB Neogi kinda rock. They're from Spelljammer, no? And those colonial hippo things?