"Should I bring up past documented issues with parents during the termination process?"

Maybe. Ideally, there was a process leading up to the termination of a parent. You should be discussing the issues as they came up and tell the parent, “If we can’t resolve this problem it will lead to your termination.” I also think it’s a good idea to give parents a final chance: “If this happens again, I will have to terminate our contract.” In other words, you should be communicating all along that the consequence of a parent not following your rule is termination. You don’t want the termination to be a surprise.

When you have been communicating all along, then I don’t think it is wise to say anything more when you do terminate. This is because it will only bring up bad feelings and the parent may want to argue with you. Sometimes it may not be possible to terminate after a process of trying to resolve a problem. For example, the parent threatens you or your staff with violence. In this case immediate termination is warranted.