I think your DH needs to take charge with his family and say that he is doing the visitation roster and they must contact him first to get approval to visit and he will give them times and days. He can have a list of chores/errands etc to delegate to anyone who wants to visit at home ie. ok, you can come at 3pm on Friday and can you pick up a quiche for dinner on your way?

I also second the phone off the hook but also a note on the front doot or gate that says "Mother and Baby resting. Do Not Disturb". I got no interruptions when I put that one on our front door.