Upbringing of a pure blood - I dislike this. It was his pureblood upbringing that made him the beautiful, sympathetic person he was, not because it was a good upbringing, but because it was a terrible one that he wouldn't allow to bring him down.
The marauders didn't fear Voldemort, they were Gryffindors!
I feel like James and Ginny would have gotten along really well. Like Harry and Ginny would start dating and Ginny would become BFFs with James and they'd have inside jokes and team up against Harry during Quidditch.