Dr. Strange must not fall under the Universal deal, which is interesting. I can't recall seeing any representation for Dr. Strange at IoA or not, but I do know he appeared in the 90's Spider-Man cartoon, and nearly everything in the Marvel section of IoA is based on those cartoons, so I would have thought he was there. My understanding is that if the character is displayed in any way at Universal, then Disney can't use it, and that includes just painted onto a mural or something. This is why Guardians can be used because those characters were not at all prominent at the time IoA was built and thus were never used.
All told, I think Dr. Strange would have been a better fit for the ToT at DCA than GotG. Of course, out in Anaheim they can use any and all Marvel characters since the contract doesn't cover that area.