I think Caedus has a legitimate chance against the Dread Masters. His telepathic resistance is amazing, his Force defenses are alleged to be turbo-laser absorbing, he can presumably teleport, and has been able to conjure illusions that even Luke couldn't see through (on multiple occasions). On the other side, it's a press to say he has the offensive firepower to pull through her. I don't see lightsabers playing much a role here given the Dread Masters love for teleportation and the Force.
Which isn't at all relevant to Caedus.
They're individually far more powerful than Sith like Darth Ekkage, the most powerful Sith Assassin in the Empire's history, above the likes of Thanaton and she's much more powerful than Master Wyllett who humiliated a pre-prime Baras before becoming far more powerful.