Questioner
Apprentice Match up: Simon vs Kylar Stern (Brent Weeks, Night Angel)
Master Match up: Kai vs Durzo Blint (Same series as above)
Doubles: Lindon and Yerin vs Atticus and Granuaile (Iron Druid Series)
Queen/Ruler Match up: Leah vs Egwene al'Vere (Wheel of Time)
Will Wight
1.) Apprentices
This may be egotistical of me, but I give Simon the edge in this contest. He has strength greater than Kylar has ever displayed, and the magic-eating properties of the black ka'kari will be of no use against Valinhall, while Kylar's own unformed magic won't slow Simon down.
I say Simon cuts his head off without having to put on the mask.
2.) Masters
The tricky part here is that the full extent of Durzo's power is never revealed. I would imagine he has the edge, by virtue of centuries more experience. Even if he can't kill Kai immediately, he could almost certainly withdraw and gather enough information for a more lethal second attempt.
That said, since he's passed on the black ka'kari to Kylar, his abilities are more limited. Plus he's lost his immortality and his accelerated healing.
Too close to call. I think it might come down to luck, unless Durzo has learned some secret magical skills over the course of his endless journeys.
3.) Doubles
I'm afraid I don't know enough about the Iron Druid series to answer this. I've only read the first two books, and I don't remember who Granuaile is. Isn't she his apprentice or something?
4.) Queens The hard part about this matchup is the incompatibility of the two magic systems. Leah can't block/shield anyone from the Source, because she's not a channeler, and she can't sense, slash, or counter weaves. In the same vein, though, Egwene can't sense Leah's presence or power, and can't counter any of her powers.
Barring balefire, I'll give it to Leah. Her eye is more likely to be able to detect Egwene's magic than Egwene is to be able to sense Leah's abilities, and Leah has access to enough weapons in Ragnarus that her first strike on an unaware target will be enough.
But if Egwene decides the situation is grave enough for balefire and gets the chance to use it, there's really nothing Leah can do but be burned out of existence.