I'd go with the parallel evolution. I think if we train hard enough we all end up in the same place. If people converge then it is one piece of evidence we are on the right track. If we are going in different directions it means we are lost. Ezra's aikido is superb - probably the best I have seen - so you have made the right choice of whom to train with anyway. Just hope some of it rubs off on you!
I've been exposed to both styles and they seem to me awfully similar in style, philosophy, technique, and training focus. However, nobody around me seems to know of any connection. If it's a case of parallel evolution, I will be very impressed by the convergence, but I'm guessing there is some branch of the family tree that they have in common somewhere.