Joachim Valentine (SH2) vs Mizuki (S4): 3-2 and 3HKO, I believe.
Joachim vs Natalia Luzu Kimlasca-Lanvaldear (TotA): ID should get her before she can kill the tanky Joachim.
Joachim vs Roxis Rosencrantz (MK): Think Roxis just blitzes straight through Joachim, but I could be argued.
Joachim vs Kraken (FF1)
Joachim vs Luna (Lunar1): ID.
Mizuki vs Natalia: Puts on too much pressure. Overlimit miight be an argument here except it doesn't OHKO.
Mizuki vs Roxis: Roxis can't handle that much speed.
Mizuki vs Kraken: Pretty similar. One has more damage, the other has more evade and speed. I'll let you guess which margin is wider/more relevant in this fight.
Mizuki vs Luna: Yeah, Luna can't buff quickly enough for this I don't -think-.
Natalia vs Roxis: Chrona Drive overload.
Natalia vs Kraken: I think this she can manage, though I'm not certain.
Natalia vs Luna
Roxis va Kraken: Mm, NE magic against Kraken... not sure it's quite enough in time, though.
Roxis vs Luna
Kraken vs Luna
Unsure/lazy on some of these, may edit if argued.
Mizuki 5-0
Kraken 3-2
Roxis 3-2
Joachim 2-3
Natalia 2-3
Luna 0-5