This looks amazing, I'm excited to see it come to fruition, and try it out ^^
In relation to your voice aspect, while I understand you have some experience working with VA's, an alternative solution could be to use one of the free voices from https://beta.elevenlabs.io/
The quality is quite high, and it's very user friendly to use (you'll have a 10k characters limit pr. month as a free user though).
Edit:
In relation to creating lip files, JCarter's put up a small video that shows how to do it, that's pinned over in the Kotor discord's "Mod Development" channel.