e a mod that allows sims to break up and neither sim move out
You'll find Cathair's stay option for breakup
HERE. It hasn't been updated in ages, but I've been using it with all EPs and SPs for years with no problems.
and a mod that allows more than 12 sims on a lot.
There're quite a few of these...the one I've been using for a good two or three years is available right here, Squinge/Chaavik's 'More family members'
HERE.