bruce lee. I'm pretty sure he used to do boxing, wrestling and jiujutsu aswel.
Jean Claude Van Damme?
Most definitely Helio would be one of the founding fathers, the gracies in general with their dojo challenges. If ricksons record is to be believed then definitely he would be the modern father. But I feel the founding fathers statement is better because MMA is not one style, oh and I was never a fan but Fedor, Royce, Frank, and Bas, (am a huge fan of Bas).
Jonathan Snowden does a very respectable job in tracing the history of MMA back in his book "Shooters", I think it lays out this argument quite nicely.
its got to be bruce lee the only time a superhero sidekick overshadowed the main hero was him as kato surpassing the green hornet.
Without him would there even be a martial arts film renaissance in the 60s and 70s or karate schools across the US?
Bruce Lee's thoughts on taking from various arts are well documented
come on somebody throw in a chuck norris joke u know u want to