I can only hazzard a guess, but IMHO, O'Sensei was proably influenced by everything he saw. Most great martial artist are.
What is interesting to me is that on some level, even without knowing it, most martial arts have a base of agreement. There are probably only so many ways to hit only so many targets and only so many ways to unbalance a person. There are bound to be a great number of similiarities/agreements.