Laguna is NOT good against Feral Chaos. It's kind of asking for disaster, unfortunately. Close-attackers in general don't fare too well against him.

Yeah, Mega Flare is Yuna. I stuffed her offensive lineup with that, and he just can't seem to dodge it. Firion going aerial is good too. toffeethesnob had killer good luck with Kuja, and I've heard CoD is good too. The good strategy seems to be grab the aerial ones and bomb him from the skies as much as you can.

True confessions: Mega Flare is what ended up turning Yuna into one of my primaries. I hadn't intended to do much of anything with her, and then MEGA FLARE and now I can't do without her.