Pippi, if you have concerns that they are going to go back and feed your X info about you, I think you are right. It's a shame, but it is what it is. Like you said, you don't live on the other side of the ocean for nothing, and why let people in your life who you doubt.
If your kids are friends w/their kids, I personally would let them remain friends, as kids don't need to be caught up in adult issues, that is just my opinion.