One Piece
-The final four is obviously bikini girl, Lucy, Burgess and male Hancock. Bellamy will get taken out by one of them quickly during round 1 as a joke.
-Burgess's presence throws a wrench into the whole tournament because (A) he'll surely cheat, and (B) either he wins the entire thing (weird, would displace Doflamingo's crew as the immediate threat) or he gets defeated by someone (also weird since he's suppose to be end-game material). However its highly likely that the tournament will not go to completion (especially with Burgess around) so that might be the author's "out".
-I assume the tournament is set up as such:
-Free for all for block A-D, resulting in 4 winners: Lucy, Rebecca, Burgess, male hancock
-The 4 winners will each face one of Doflamingo's 4 underlings that were previously shown
-Any winners of that fight will get the "chance" to fight Diamente for the devil fruit (and he'll surely cheat)
-Previously I guessed that the missing samurai would end up in the tournament and be the one to eat the devil fruit. Assuming Rebecca isn't the samurai (don't bet on it though), I think she also has the greatest chance of being the one to eat it because she's obviously the friendly character of the arc. It would suffice the same storytelling reasons as if the Samurai ate it.
-Speaking of which, Rebecca could be the missing Samurai. Especially if that bikini armor turned out to be a dragon scale bikini...
-And finally, there's a 100% chance we're going to get "Rebecca for nakama" posts for the next year.