"I saw a GameFAQs topic discussing the avatar logbook and if there's any way to make an avatar in one save and recruit them in another, of course without having to beat the game to add units to the logbook at the end."
Just noticed this part. The way I was doing it before was making my units to the end of the game and then saving them there, but the problem was that every single avatar I saved just got overwritten when i pressed Update on my main profile. I thought this was a way to get for like 100 different MUs.