So as promised, I'm slowly trying to help this mod forward.
Getting it to anywhere the level of Birthright or Warhammer will take a very long time and a team of dedicated scripters, but I do think it can be made playable pretty fast if we cut some corners and integrate existing mechanics from Birthright/Warhammer where appropriate.
For example Silfae has given permission to use his awesome Warhammer portraits, so here's a proof of concept of how they can be re-tinted to represent sun elves, moon elves, wood elves, and drow (all credit goes to him obviously, I just - very unskillfully, in some cases - changed the skin tone) :
I'm not quite sure how I messed up the sun elf woman's mouth while making the skin bronze-ish, nor why the drow do not have the white hair I'm pretty sure I set them to have, but these are minor details, surely!