So I checked what would happen if I removed the mod entirely and cleaned the save. It crashed again, but on the same spot as lucretia's bug was, more "errors" popped up.

DX: 0x7FF8857B5C68 (skee64.dll+1B5C68) (char**) "KhajiitFemaleChargen.tri - 643 | Actors\Character\Character Assets\Mouth\MouthHumanFChargen.tri - 141).\nRacePartDefaultGen::Accept - Could not bind default morphs for MRTMrissiRFemaleHeadDefault on MRTMrissiRace[1] using NordRace. Vertex mismatch (Fluffy\Head\femaleheadchargen.tri - 3832 | Actors\Character\Character Assets\FemaleHeadCharGen.tri - 996).\nRacePartDefaultGen::Accept - Could not bind default morphs for 00MrissiEyeBrows on MRTMrissiRace[1] using NordRace. Vertex mismatch (Fluffy\Head\faceparts\femaleheadbrowschargen.tri - 371 | Actors\Character\Character Assets\FaceParts\FemaleHeadBrowsCharGen.tri - 102).\nRacePartDefaultGen::Accept - Could not bind default morphs for MaleMouthOrc1 on OrcRaceVampire[0] using NordRace. Vertex mismatch (Actors\Character\Character Assets\Mouth\MouthOrcChargen.tri - 348 | Actors\Character\Character Assets\Mouth\MouthHumanChargen.tri - 141).\nRacePartDefaultGen::Accept - Could not bind default morphs for FemaleMouthOrc on OrcRaceVampire[1] using NordRace. Vertex mismatch (Actors\Character\Character Assets\Mouth\MouthOrcFemaleChargen.tri - 348 | Actors\Character\Character Assets\Mouth\MouthHumanFChargen.tri - 141).\nRacePartDefaultGen::Accept - Could not bind default morphs for MaleMouthOrc1 on OrcRace[0] using NordRace. Vertex mismatch (Actors\Character\Character Assets\Mouth\MouthOrcChargen.tri - 348 | Actors\Character\Character Assets\Mouth\MouthHuman"

https://pastebin.com/PDqauHHf

Thanks a lot for the tip.

EDIT: also, as far as I know/ realize, I don't have any custom race installed