Most likely none of these guys would go through that list undefeated, but who in your opinion had the best chance to do it and why.
My personal choice would have to be Lennox Lewis. This man always seem to be underrated by most. Lennox had his huge height and size that he knew how to use well. A long powerful accurate Jab, and a sledge hammer right. Also had his deadly uppercuts and left hook. Basically had all the tools in his arsenal. Lennox had a decent chin and above average hand speed for a heavyweight his size. The most important thing Lennox had against most of his opponents was his smarts in the ring and his amazing timing. With all those tools I think he has the best chance to defeat everyone of those fighters in this list. Of course everyone here is in their prime just in case your wondering. I could only choose 10.
Muhammad Ali
George Foreman
Joe Frazier
Mike Tyson
Lennox Lewis
Vitali K
Joe Louis
Rocky Marciano
Jack Demsey
Larry Holmes
Ali fought and beat the best competition of anyone on that list, so he is an easy choice. Giants like Lewis and Vitali would be tough for anyone, but Ali had the smarts and skills to beat them.