converted follower ctd help

[sumarita]

i've been trying to convert a standalone follower of mine to SSE without any luck, he shows up ok in game but the screen freezes and i have to force exit the game. i believe i have checked everything, nifscan can't find any errors on textures or meshes and this is the only follower so far that gives me this issue since i have succesfully converted other mods before. the mod won't crash ingame if i keep the facegen made by the SSE CK but that changes his face entirely 

 

is there any experienced modder out there that can point me in the right direction maybe? i can provide the original oldrim mod if anyone wants to try and help me, thanks