Oh to be young again....

Your ex might be saying these things now, but if she had a problem before she'll have a problem again. If you choose her you're going to be on again off again until one of you decides to put your foot down and see other people. It's up to you but I think I'd give it a shot with the friend

Still time to change the caterer. Honestly your FIL is probably right, it would be a good idea to serve more food.