Magic Fanatic: Yeah, Light/Light/Middle most likely (I'll take Jo'ou's word on Team EB). As for Mother 3, as best I can tell you're the only one to have played the game, so sorry. For the bosses... eh, we've already got an SMRPG boss. Zalera can make his way directly to Light since he cannot take a hit in-game and is way too easy to blitz. Kuwadora is more a boring High Light, that lack of MT or status means he's utterly walled by a healer who isn't OHKOd + 1 other PC. Zeromus... my understanding is that the DS Zeromus is a huge disappointment in-game and Meeple's stat topic makes him look better than he really is, but even given that, a 2-turn charge time on something that isn't a OHKO vs. the actual HP average isn't real impressive. He does have Limit good spammable damage, and his limit range is pretty huge unscaled though, which makes him a great counter-boss slugger and tricky to blitz. Also I assume that Meteor sucks a lot more vs. PC teams and Meeple listed the focused damage average, but maybe you can clear me up. Dunno, Middle? Seems to kill bosses but be destroyed by any kind of MT healing.
Jo'ou: After some further chat in #rpgdl, Edna definitely his Light for lack of crowd control, and Exor got knocked to Middle for just not having the broken stuff Heavy bosses need. (Also Jr. has *Lock* hype against Edna so that fight isn't as cut & dried as you might think.)