Sorry for being dense, I don't understand how it would break the rule? If Heir #1 finishes their requirements, then clones the townie to get the baby spouse, and uses life extending techniques so that when the spouse becomes a young adult, they are then the same age to try for Heir #2. I just want to get clear before I even start.
Also, another question, if a founder/heir joins a career/profession, but does not max it, does it invalidate this career as a career requirement for other heirs?
More questions - can other sims come and go from the household as they please? So I could move in a spare, then promptly kick them out?