Winners so far:
Round 1: Avendar with Lion-o
Round 2: Freija with Aang
Round 3: Raynor with Finn
Now for Round 4!
Strategy: I would go with Steven. We're both healers who specialize in defense who don't really want to fight, but to solve a conflict. Ultimately, she'd tell him to use a bubble or shield to block hits until the other fighters are tired out, and then try to use conflict resolution skills to end the fight.
Player 2 - Kindrianna. Character, Leonardo.
Strategy: I'd tell him to utilize his ninja stealth and lifetime of training to strike at superior opponents when they are vulnerable or least expect it.
Player 3 - Pilpus. Character, Korra.
Strategy: I would probably go with Korra, as Korra is the most attuned to the elements, which is what I'm all about. As for strategy, Korra arguably has the most raw power on this list, only comparable to Aang but I’m assuming Korra would have access to all of Aang's memories via the Avatar spirits or whatever, meaning she could capitalize on all of his weaknesses. Assuming nobody on this list has the ability to manipulate time and space (which I’m not sure on Steven Universe's power set), the incomparable versatility of the Avatar is basically unbeatable. She has the ultimate defense and offense that fits Pilpus’ perspective the best so from there it’d just be out maneuvering the competition with her superior versatility.
Player 4 - Daekara. Character, Samurai Jack.
Strategy: Of the fighting styles I know Samurai Jack is closest to mine. Strategy would be to parry and dodge then counter attack when openings appear.