I think in fact only about 5-10% of the figuring out was done by me, the rest is off of docs other people have written, with a BIG kudos to Garyong who's been helping me figure out the sprite formats. Understanding how to read the hex is something that takes a while, though it helps to have a decent hex editor too! My app's hex editor sucks, but hopefully that will get better in the future!
NSMB, Ben 10, Harvest Moon, Pokemon, and Zelda are my prime resources for debugging 3D stuff, mostly because they've got a wide variety of all the 3D file types, which are easy to locate since I've memorized the rom layouts. There were also some models from Ben 10 which still weren't rendering properly in the old build (such as Hex). Harvest Moon also has the most warped bones list which require stuff to be rendered in a specific order.
I think it's going to be a lot of work just getting Textures and Models supported, so motions/animations are still a fair way off yet :p
Textures are taking a while, mostly because I have to improve the data structure for graphics to allow for non-paletted/compressed/etc formats, as well as accessing internal assets, I've also been going over and updating the spec now that I'm a bit better at understanding the file structures.
You can view the updated spec here
, and I haven't updated any of the 2D docs, just in case anyone checks :p