Darth Traya vs. Darth Zannah

Force, sabers, all out

Both are prepped, but Traya's giga drain is disabled

Zannah in all three, and since I don't believe that giga drain is unstopable weapon, I would say Zannah in all three, even if Traya's drain wont be disabled.

Traya and Nihilus are the most overrated characters in SW in my opinion.

I'll go with Zannah as well. She can defend against anything Traya can throw at her.