I intended to carry this further, but as the author has cozied up to Nazis and started denying the Holocaust, I no longer feel comfortable carrying on with this or any other Harry Potter related work. In any event, I think I have finished with everything that I can do even a mediocre job of exploring. Given that, I'd like to talk about the things I consider most important and put out there ideas that I had which others might like to pursue.
Anyone familiar with Tim Drake's origin story knows this but I believed it essential even in this fanfic for a young Bruce to have a Robin to act as his ally and conscience. The best Batman stories always remember the importance of that relationship, that Batman is nothing without Robin. For an eleven year old Bruce, Robin taking the form of a literal bird fits. With, perhaps, the exception of the Sorting Hat scene, Robin's introduction is my favorite moment.
The riddle was, "Why do some people have magic and some don't?" The answer was "Sometimes things just happen and there's no discernible reason."
I considered continuing this story by following the true "Riddle of Ravenclaw" further. This would ultimately lead to the answer, magic derives from Atlantis. Though it can appear anywhere, for reasons known only to itself, they were the first to harness and try to understand it. By making contact, through the portal that Ravenclaw created under the lake, Hogwarts might contact Atlantis. In a year, a young Arthur Curry (Aquaman) might attend the school.
Yes, in this continuity, Thomas and Martha Wayne were murdered by Jack Napier. However, Joe Chill was arrested and convicted. As it will happen, Jack stumbled on a vagrant and paid him a tidy sum (the cash he'd pulled from Thomas Wayne's wallet) to hold a firecracker and let it go off in his hand. This was enough for junior detective Bullock to arrest him and ADA Dent to secure a conviction.
In a future year, alongside her mother, fleeing from the law, a young Selena Kyle might attend Hogwarts.
As Minerva McGonagall allows Alfred Pennyworth to court her, she might accept fewer responsibilities and finally hire a replacement Transmogrification professor in the form of Jason Blood.
An ideal future Defense Against the Dark Arts teacher exists in DC in the form of John Constantine.