I don't see him beating KCM or early EMS Sasuke. He struggled with Taka Sasuke after he started using MS, and even before he was keeping up with Bee fine, despite intending to capture. It was only down to lack of intel that Bee got him twice (not knowing that Bee could channel raiton too, not knowing that genjutsu doesn't work on Perfect Jins).
The only way I see Bee beating either is through Renzoku Bijuudama, but both would probably end up "nipping him in the bud" before he reached BM.
Bee can't handle Amaterasu... it was the need to keep him alive that Sasuke ended the technique himself.