I was just rereading the chapter when something occured to me....if Neville and Harry had chosen purebloods to begin with would Dumbles have still interfered? I think he would have anyway just on general principle because he hadn't chosen them and of couse he knows best.(not!) Did he attempt to interfere with James and Lily, or he try something and get slapped down by James, Lily, and/or James's parents? Or was it only certain couples that he messed with? Since he enjoys micro managing other people's buisness I can't see him stopping just because Voldy got away. Did he just use other means until the latest fiasco with Harry and Hermione? What a concited, manupulative creep he is, I hope that he loses everything he's valued so much, he school, influnce, power and reputation. Truly I have enjoyed this story, and appriciate all of the work and thought you have put into it!
Author's response
That depends. Dumbles is concerned that the 'Chosen One's mate be acceptable to the old families of the light (an arrogant bunch of prejudiced bastards) Ginny, from a light aligned family would work, so would Sue Bones, Daphne would not (since her family is seen as a Dark one.
Did Dumbles interfere with James and Lilly? Well since it is one of my conjectures that he put them under fidelus instead of getting them out of range, I'd say yes.
Harry is working to remove everything he cares about from Dumble's grasp.