Cool that you brought this back, good times.
Archers (FF3 Ranger, FF5 Ranger, FFT Archer [male], FFX-2 Gunner Paine)
Engineers (FF4 Cid, Edgar, Mustadio, Worker 8)
Red Mages (FF1 Red Wizard, Tellah, FF5 Red Mage, Vanille)
Paladins (Cecil, Agrias, Meliadoul, PC Beatrix)
Archers vs Engineers
All the Archers have are damage, but it should be enough to ensure Edgar never takes a turn without some blocks, and the rest of the Engies suck. It takes awhile to grind down W8's defense but whatever.
Archers vs Red Mages
Letting any of FF5 or Tellah live is terrible, and Vanille living is pretty bad... I don't think the largely MT & unfocused burst is enough to reliable get 'em all. Could be convinced.
Archers vs Paladins
Dat auto-protect'd Meliadoul who goes around breaking shit.
Engineers vs Red Mages
Vanille status should mean that Edgar never gets a non-status'd turn. W8 is a threat but the Red Mages have revival & healing, they can outlast him, especially if he's killing himself to do more damage.
Engineers vs Paladins
Too much status blocking for the Paladins, sure. Air Anchor might nab one but it'll be too little, too late.
Red Mages vs Paladins
This is the tough match. Suspect PC Beatrix scaling issues are here, with high Beatrix respect giving it to the Paladins from enough damage inflicted to keep the RM's revive-locked, while low Beatrix respect meaning the RM's can both undo the Paladin's offense as well as land some damage / non-immuned status. Kneejerking Paladins but this is the easiest match for me to switch my vote.
ALL of the Archers, Engies, RMs, & Paladins vs Rikku*, Tidus, FF5 Samurai, Garnet
Initiative Hastega, Slowga, Zenigage/Gil Toss + Garnet summons + something unfair from Rikku. Maybe Worker 8 & Meliadoul will see a turn? Yeah, annihilated, especially if kept to a mere 2 picks per team.