I think I have more information regarding the relationship issue I experienced, with the "20 friends" Charisma bonus not applying. I think it doesn't count sims not in your current town. The trouble is, it applies the relationship penalty to everyone in the world when you are falsely accused. My sim had 20+ friends before going to University, after 3 false accusations he now has 6. And the bonus is no longer applying in the home town.
I tend to do the activities that slowly raise relationships among multiple sims, so it's very easy for my sim to make many friends and then lose them again. Though in University, my sim was being falsely accused with every single friendship lost, which wrecked every other relationship.