Um, Obi-Wan managed to almost cut through several layers of blast doors protecting the TF's Lucrehulk command ship in tPM, only very few, very special materials like beskar or cortzenite can stop a light saber or slow it down in some way.Yeah the Predators smart but the other two Terminators here can reasonably resist a lightsaber except maybe the T-800 but if it's equipped with slug throwers it would do better than anything in the Predators arsenal.
Not saying the Predator is completely ineffective but a lot of his stuff can be sliced by a lightsaber, the plasma caster can easily be dodged or deflected and the wrist blades is suicidal.
Best bet is sneak attacking while Ahsoka is distracted, in a 1v1 Predator can't really do anything and that's the pretense I had in mind for my original comment.