Correct me if I'm wrong but didn't Jackie say his "fight" training is purely for film. He has no practical experience in an actual fight.
Donnie Yen practices MMA on top of muay thai, boxing and bjj.
The Westerns are larger and have more real world sparring experience. 3 -1 with Chuck being the weakest.
I want to say Lee is a better fighter than Yen, based on hype alone but I can't call it. I don't believe Yen or Lee could beat prime Scott, or Van Damme who are both winning prize fighters. Jai may not be a fighter, but he is a legit martial artist and a nerd about combat sports, on film and IRL. So he's a larger Donnie Yen.