I've had quite a few University sims move in to my sim's household - back in his home world though, not in the university world. They were all best friends. I've also invited university sims over, introduced them to his children, and had them invite to move in and marry. I don't know about how such sims some become "incomplete" though. I generally married them off to my sim's children and then moved them out of the house. I always use the "invite foreign guest" option and invite to move in when they arrive. I have heard (if I understood correctly) that using MasterController to add university sims to the household can cause corruption if the sim is a tourist. But I have never done that.
Note: all this was in the home world. I never married or asked a university sim to move in while actually at university. Also, I use lots of NRaas mods, I don't know if that would make any difference as to "incomplete" or (I'd guess) corrupted sims when moving them in to the home neighborhood.
edit: I've since found a thread on the NRaas Chatterbox which says using the MasterController Add Sim function is the best way to do this. I had no idea the other way could corrupt sims or games.
