One for the guest sprite and one for the join sprite .
Rafa/Malak only have 1 sprite in UNIT/WILDFACE.BIN that is were you have formation sprites, messing with the guest version that appears in some scenes will make things go wrong. At least currently there is no easy fix, since guests are linked to shared portraits (and that's coded).
So... Short answer for the PSP version:
No, but I'm sure it can be possible for PSX. Maybe it's possible with a hacking code to link a formation to an unused sprite and changing everything there. But since people don't usually mod the PSP version due to the limitations I guess you have to give on. For example I'm looking at a possible solution for Onion/Dark Knight and I don't find anything.
Edit: Best answer:Quote from: Xifanie on April 14, 2017, 01:40:38 amAfter characters join your party, they lose their custom assigned Unit ID. THEREFORE, events that are post recruitment such as golgorand execution site will NOT trigger talk events mid-battle between Agrias and Gafgarion because the game will think Agrias is not there! You would have to edit the event conditionals to fix this... and well, you already gave up on eventing, so...
Someone feel free to correct me if I'm wrong, but I think fusing Guests into their Join counterparts is the best course of action; just keep the Unit ID for the Guest Unit ID when the character is supposed to be a Guest, so that way, events will still trigger just fine.