Green survived a near prime Mike Tyson. Dempsey and Marciano had similar styles, with important differences, however they were 20-30 pounds smaller than Mike Tyson. Could Green survive them or even beat them?
I think he would have a better chance of surviving them than beating them, for whatever that is worth...
Green definitely was a good survivor. If he fought just to hear the final bell, he'd probably be successful at it.