I thought of something else. Once you do move, you can visit your old house, but not for a while. If you go back too soon then it will delay the feeling that the new house is *your* house. In our experience moving several times, it's best to wait at least 6 months, although that might be harder since you live close by. Usually, once you have had 1/2 a year to a year to settle into your new house, when you go back to your old house it's nice, but it's no longer *home*.
Also, I like the idea of setting up playdates with some of his current friends. Maybe, working on the idea above, though, I'd attempt to have the kids come to your new home or have the kids meet at some neutral location.
But, definitely, don't feel too guilty about making your kids move. Kids really are resilient and you have to do what is best for the entire family. The kids may even thank you some day!
