[Faceman]

just tried it out myself
the high level issue is indeed the problem
and the multiplayer workaround works just fine
however you will meet high level incarnations of all NPCs after that
unless you go back to multiplayer every time before recruiting and add in a low level PC - then readd your PC and go back to single player.
You could also use CLUAConsole to spawn the lowlevel incarnations and have them join immediately thus hoping their bigger twins won't show up