Is it possible to fix the Conscript Sergeant model with the provided tools?
It really depends, thing is, a lot of models especially EF ones, comes without heads and arms. They both are part of head (thats why pretty much grenadier vCoH model is broken and has no arms and no hands).
Considering tecnically all inf models in the game uses the same skeleton and same animations can be appyed to them, there must be something wrong happening not with he Cons Serg model iself, but with how its codded.