Hmm my memory isn't best but surely original Aerith model didn't had 47 parts, dunno if you made a typo writing it or count something wrong, it should be more like 27 or probably even less. it was more than a Cloud(17 parts) by dress parts and hair. Surely not 47 dunno what you count as parts

. Character battle model parts starts on file **am and are limited untill **ck which is first weapon, feels alot, but usually they have just around 2X parts. And you need to reuse all of them if you don't want any errors and for best effect. Through you could always add somewhat "empty" - transparent parts in case for example your Aerith model was wearing pants or had shorter/different hair making those additional dress/hair parts useless.
But anyway I dunno from what you got to think Aerith original model had 47 parts. You can get all that info in file reconstruction project:
rvam 3.5 K Aerith: Hip
rvan 6.0 K Aerith: Chest
rvao 15 K Aerith: Head
rvaq 1.1 K Aerith: Ponytail part 1
rvar 1.1 K Aerith: Ponytail part 2
rvas 1.1 K Aerith: Ponytail part 3
rvat 704 Bytes Aerith: Ponytail tip
rvaw 3.1 K Aerith: Left arm
rvax 1.8 K Aerith: Left forearm
rvay 3.0 K Aerith: Left hand
rvbb 3.1 K Aerith: Right arm
rvbc 1.8 K Aerith: Right forearm
rvbd 3.0 K Aerith: Right hand
rvbf 1.7 K Aerith: Left tigh
rvbg 2.8 K Aerith: Left leg
rvbh 1.7 K Aerith: Left ankle
rvbi 1.2 K Aerith: Left foot
rvbk 1.4 K Aerith: Rear upper dress
rvbl 1.2 K Aerith: Rear lower dress
rvbn 1.7 K Aerith: Right tigh
rvbo 2.7 K Aerith: Right leg
rvbp 1.7 K Aerith: Right ankle
rvbq 1.2 K Aerith: Right foot
Giving all - 23 parts and for best effect you should recreate them all, or at least most of them(as I said before you can use transparent parts if your model have shorter hair for example) to make nice looking model. But if your model have for example foot and ankle as 1 part, you should cut it for 2 different ones. Same if arm and forearm are one, cut it to be same as in orginal model, otherwise it'll be pretty much useless and look bad even if you find a way to build own ff7 skeleton and reanimate everything yourself. You should know mesh doesn't deform in ff7 engine and animation is actually a bunch of objects put near that's why you MUST cut your model for parts corresponding to single bones. In case of Aerith that would be 23 bones like you see in the list above. And that's also why you need to close every part you cut in a nice "round way" as they'll be "connected" only by moving one part a little bit inside of another, you should open any existing model in Kimera and see some animations to understand that better.
Edit: I guess you got 47 by counting everything in the list inside Kimera

23 model parts, 23 bones and a weapon >.>, well now you know you only need to recreate model parts, as you use existing skeleton with it's animations for making it much easier.