This is a gloriously well-done AU; I'm especially in love with the way it folds all the available canon into the invented universe of the story concept, and makes it work - I like the nods to the other fic you've written that I haven't yet commented on in the trail I've spent this evening blazing through your archive (I'm sorry! I'll leave proper comments on the morrow!), it makes it feel like it's not just consistent with the canon but with a certain highly enjoyable take on that canon, if that makes any sense. I love stories that treat Xanxus and Tsuna like the twin pillars of the Vongola family in its later incarnations, and this story pings that kink so hard I am helplessly fond of it.

I especially loved how you handled the revelation of the six Funeral Wreaths; it's a solution I wish had been possible in the canon itself rather frequently.