This is really odd but I sort of fixed it: I uninstalled all mods, then uninstalled and reinstalled the base game. I put only this mod in, and installed both Yuthura's head and Twin B. It crashed with Yuthura (character creation still fine, crash was when your character wakes up) but was fine with Twin B and she was the other one I really liked, so I'll just go through the game with that head. It could be related to her outfit? Obviously you're the expert here, but I noticed that Twin B loaded up with her twin suns outfit, and I could see it in character creation too, but Yuthura was shown in in default class outfit in creation. I looked through file lists and don't know what would be causing a problem, my only theory is her default clothes couldn't render or something? I did not mess with the optional clothing installer this time, just the base installer. Anyway, I'm glad the rest of it works and I'm excited to do my playthrough!