Of course you can weight drain if you please down to CW. James Toney is supposed to be there as well instead of 'James Cunningham'
I'd say Holyfield, purely on the basis that if I saw him get in the ring with any if the others there I'd be worried for his health. So I suppose by default that makes him the weakest for me.
Odd question. They're all less than ideal opponents if you're a solid 15 stone. I wouldn't want to kill myself to face Yoan Pablo Hernandez in a fight with absolutely no fanfair.