Re Dudley - yes, I think Rowling addressed this is a post book interview. She said that she pictured Harry and Dudley being the type of family that exchange Christmas cards and that Harry might stop in for a visit occasionally with the children (and his children hate it.) It's why I threw in that line towards the beginning of VVV about Harry seeing Dudley at Christmas and it being "awkward as usual."

Re Teddy - I agree. It's part of the tragedy of Harry Potter (or of Remus Lupin)...blood-connection aside, Sirius couldn't bring Harry up because he was in Azkaban, and Remus couldn't bring him up because he was a werewolf who barely scraped by. I like the stories where Harry brings Teddy up too. From the sounds of the epilogue, Teddy just came over for dinner a lot :P It's why in my story, I have him staying over...almost like Andromeda and Harry have joint-custody.