I paid good money only to have my dog NOT do what Jasper does
As I recall, my dog's trainer wanted all the dogs to "ask" if they could/should do things, just like Jasper is doing. Of course, my dogs seldom asks, and barges before me up and down steps....I will admit she is good about coming inside, she does wait for her lead to be taken off.... I, too, would like to trade dogs.:D My trainer would have loved your dog.
I would wait until the kittens are re-homed, as you mentioned, and then try a new round of behavior changes with the pupster. He sounds so smart and easy to work with, that it seems a shame to have the leader worked up about the doggie door. I bet he'll do whatever you want, you just need to rework the steps in and out the door....my trainer always talked about "sweetening the deal" to get the dog to do whatever!
By the way, I know not what I talk about, so don't take this typing as instructions, just suggestions. :D
I, too, would like a photo of this perfect dog, Jasper!