Julio Cesar Chavez Jr.
Hector Camacho Sr. (RIP)
Those are 3 that I know of off the top.
Yes I could give you some names but they are not well known fighters . I can tell you this there are a few boxers that smoke . Look boxers are no different than anyone else in society they do the same things not as many but some do.
Lionel Rose, an Australian,who was the World Bantam weight champion smoked a pipe, before and after his fights.
No successful boxers because first of all it's bad for you despite what people say and yes it does cause lung cancer. On top of this they would get banned for doping even though it's not something helps you perform better it's an illegal drug.
Probably. There's quite of few MMA fighters in the UFC that do.
I can't believe no one said early Tyson. Mike Tyson even said it! Although it didn't do much to him, he was in his prime i think.