Now I remember...

[Lord Xehanort]

Have Ramza as a Ninja with Martial Arts, Move +2, Punch Art and Blade Grasp... actually... have EVERYONE with Blade Grasp. Also, have some of your allies with Train and doing enough damage to bring the monsters down to critical status. This SHOULD turn them on their master (I never tested that).
Now, have your Ninja-Monk-Samurai blend Ramza run forward on his first turn. His equipment should be a Black Costume, a Thief Hat, and Germinas Boots. He should be able to leap the small chasm and run up to the Chemist and hit him from the side. Dead Chemist. Also, Ramza will draw some fire from Balk (which he will block with Blade Grasp). And the monsters will turn to him as well.
In the meantime, have Orlandu and one of your friends run in from the bottom (across the bridge) and take the Behemoth. They'll draw the white dragon's fire as well, which may miss on all three shots. Take the beasts one at a time, while holding them with Ramza. Kill everything, then swarm Balk.

[BG-57]

Actually the only thing you need to do to win is to kill Balk. If you're lucky, he'll charge instead of retreating. This is where Math Skills really pay off since you can hit enemies on opposite sides of the board.

BTW, don't bother stealing Balk's gun in the Lost Sacred Precincts battle. You only have a few battles to go before the end of the game.

[Despotus]

I've a couple of comments and answers to your questions, Ansem. First, inviting a monster using train will turn them into your allies (as guests), however, as they are critical, they'll run away. You'll need to heal them up before they'll do any fighting. Secondly, use Move +3 if you have it. Why settle for +2?

[Sasquatch]

What gives Move+3, and how do I get to it?

[BG-57]

Bards can learn it for 1000 JP, so only your male characters can learn it. Consider it compensation for not being able to wear perfumes and ribbons.

[Lord Xehanort]

I've a couple of comments and answers to your questions, Ansem. First, inviting a monster using train will turn them into your allies (as guests), however, as they are critical, they'll run away. You'll need to heal them up before they'll do any fighting. Secondly, use Move +3 if you have it. Why settle for +2?

Okay... I knew that they would be critical and would retreat, but that would keep them from killing you, which helps greatly. Balk is the smallest threat compared to the monsters.
.
Secondly, I had no Bards... I couldn't get Move+3.