I don't see Tenebrous deflecting turbolasers and cannons that can bust the hulls of Republic cruisers, whilst massively pre-prime, so I think Ulic can handle him.
Kun vs Plagueis is a very interesting fight, but then again, Kun's already compared well to his successor in numerous sources. Not to mention, Kun's got a mountain of feats in combat that Plagueis just doesn't compare well to. Nor am I entirely certain that Plagueis is even capable of knowing of many of Kun's Force techniques per Luceno.
Ulic managed to use Palpatine's speed on a dark side nexus and Exar was able to keep up with him. Ulic had capable reflexes even after he 'lost' his connection to the Force. Therefore, I don't see how these two are better than Ulic Qel-Droma and Exar Kun. A lot of PT characters' wins come from their hype and misunderstood depictions.