You know what I think? Puppets aren't going to be enough to solve this matter.
Well, I mean for each individual mod, this is a workable solution, but what of all the other recruitment mods? This could all get messy very quickly.
I think that an armband should be made to accommodate these types of mods specifically. Not only could you efficiently switch between the vanilla tsl party members, but between custom recruitable characters too.
Oh just imagine... the only thing I wonder is if party members' stats/item slots are saved when they're removed from the party...
Meh, it'd be quite complicated.