There's no need to resolve the matter of Master Sifo Dyas. Last time I checked, the Sith are all about deception, mystery, and misinformation. I like the idea that the Jedi can't get to the bottom of that one and that we have no answers. Besides, it was inferred, at least from my point of view, that Dooku/Tyrannus was partly responsible for the misdirection when Jango Fett named Tyrannus as his recruiter.

Give me mysteries. It doesn't all have to be spoon-fed to us. Let us be just as much in the dark about the whole truth as the Jedi and the Senate were.