Oh, I totally shouldn't have been reading this (so many things to do!), but I literally couldn't stop. That was wonderful. I feel Petunia is one of the most underused/underestimated characters in canon HP and it's wonderful that you devoted a whole story to her and to developing her character. (if anything, you excused her a little too much, for my taste, laying practically ALL the blame on Vernon...)
Alice's little story was absolutely amazing and heartbreaking and your Augusta is ♥
And Harry... well, I've never really been a fan but you definitely got him. (he WOULD get jealous about Neville's parents... Grrrr)
Oh, and Percy's rationalization on kissing, ftw. They do make quite a nice couple!