[andrewas]

I have some very faint memories of this. I suspect it was fixed in a patch, so if you want to do it, try running the out-of-the-box version without installing TotSC.

Alternately, there is a CLUA cheat that will let you recruit anyone (though if you do someone plot-critical the game might break) so you could recruit them that way.

Or you could use create a multiplayer game to duplicate those characters at game start, and then copy the save into the single player folder.