The only issue with this being the case is the fact that there hasn't been any legends in the Gotham Universe that points to any vigilante before the events of the show, but that doesn't mean it can't happen. Also another major thing that Gotham has tried is keeping it realistic. Granted the writers are trying to find that balance between realistic and comic book like, but throwing a vigilante into the mix pre-show's history would be going far too comic book too soon.
The Court is usually made up of the upper class of Gothamites, making Thomas Wayne a prime candidate to be a court member. While his status says one thing, the content of his secret office says another. Since this is an Elseworld, and the show is more realistic than the other DC television shows, the Talons could be reimagined as normal hitmen, needing guns and a bulletproof vest to get the job done. With Thomas' doctor background, his knowledge of what could kill men as quickly and quietly as possible could make him a bigger threat than most hitmen. Him being a hitman would explain the blood and weapons in the cave, as well as a computer to keep the orders in tact, but as I said usually the rich are the members and poor are the Talons, but
We won't know the truth until way later in the season, but thats the beauty of Fanboy Theories; to allow the viewers to think. So what do you think Dr. Wayne was up to? Leave a comment and I'll see you next time!