Just focus on the mission at hand, sell the house. Get a place he has no history in or claim to. Let the kids put pictures of him in their room if they want to. They won't bother. Give them a choice, and they'll for posters of rock stars and their choice of super hero. He is neither.
The only way they will put his picture in their room is if he comes over and guilts them into it.
Then fill the common areas of your new home with bigger better pictures of them with you, smiling from ear to ear. Have professional shots done for framing somewhere. The kind that say "we are a family"
