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.
Okay but now I'm imagining George with the Potter kids and Rose, and finding Scorpius very suspicious, but then Albus and Rose assuring he's great and Scorpius agreeing like "Rose would be able to beat me into a bloody pulp anyways".
Sirius would do something like that, it's Sirius Black, total drama queen, how could he not? And McGonagal would've been so happy because finally they were together and she had won the bet against slughorn