I would say Chavez with a translator, if a translator wasnt available I would say Oscar. Both men have great resume's. I would ask Oscar about the Tito fight, the brutal KO from Hopkins, if he feels he really beat Mayweather Jr. and more recently why the hell he picked Manny as his last opponent.
I would speak to Barrera, by far my favorite of the fighters mentioned, and I would make sure to thank him for the spanking he put on Hamed.
As said above, I'd talk to Morales and tell him that Barrera was talking bad about him. Then I'd do the same for Vargas about DLH.