I think Pedro Diaz or Nazim would be a great choice for Khan. Khan is what he is and you cant turn him into some kind of defensive wizard. Diaz and Nazim are great fight tacticians and could formulate a good game plan than maximizes what khan does best.
I for one this Lucas Vs Mayweather would be an amazing fight. Lucas is IMO bigger than floyd and would be the biggest puncher he has fought in his career. I think Floyd would be way way to quick and pot shot lucas to a wide wide UD but how would Floyd react when Lucas starts hitting him all over his body when floyd lays on the ropes. Lucas hurts EVERY opponent when he hits them and with Floyd being older will be interesting to see how he takes it.