Here are a few things to try:
Stop taking them to the dog park for now. The more they behave inappropriately, the more it will happen in the future. We don’t want your dog to hurt themselves or others.
Increase her exercise with more walking or try a doggie daycare where she will see the same people every day.
Take them to people heavy areas on leash. Allow them to sit and watch people walk by. A busy park is great because it will allow them to see people walking, running, playing sports, etc. Praise your dog lavishly as they sit calmly.
Take them to an obedience class. They sound like they are well behaved in general but we also want to make sure they are responsive to your direction. This will allow you to call them to you when they react to a person.
Once they have settled in more to your house and their life, try the dog park during a calm time. If they show the behavior, leash them up and leave the park. Then take them to the outside of the fence and have them watch the person. Give them treats and praise as they sit calmly. If the person is okay and the person is calm then have the two meet.