I don't think I think the Vernon I depicted was much of a stretch from canon, though I agree canonically he's only shown being abusive to Harry. Still, I think if he would do be as he is with Harry for an accident of genetics, it's not unreasonable he might also be generally violent, and he's never shown as being loving toward Petunia (proud of Dudley, yes).
Anyway, I'm glad you liked her moving on and her journey.