it appears none of the colors I picked in VRoid Studio is applied (different strands of hairs are different colors for example)
Are you using vertex colors or material colors?
Can you send me VRM file?
It would be nice to see this be open-sourced
I don't have such plans, but this could be changed.
Might be nice to add VR hand controller support (such as the Index controllers), for people who have them, but no Leap Motion. (Also, you've gotten Leap Motion to work on Linux? Wow!)
I don't have VR controllers. Leap Motion still works, but it stuck on old SDK 2, because developers abandoned Mac and Linux platforms. You can also use regular webcam for the hand tracking, it kinda works but still buggy and unfinished.
I could open source some plugins or API and make a documentation for it in near future. The app is plugin based, so it's pretty easy to add more tracking devices to it. But I doubt there are more Linux VTubers.