Wow, old thread. I might as well list mine, though
Lazlo (duh): RoP (double duh), Rage Rune, either killer/counter rune.
Snowe: Killer/counter rune, other attack enhancing runes.
Ted: Soul Eater, Flowing rune, some other rune that didn't get used...
Sigurd/Lino: Sigurd with water or flowing, Lino with killer/counter. (Lino was 2nd playthrough, other party members stayed the same).
I don't remember my exact rune set-ups but basically I just spammed True Friends Attack, Ted's Soul Eater spells, and just attacked with Sig/Lino (Sig healed when needed). No real effort is required for this battle so I didn't bother with the level 99 thing or extensive set-ups. The tree was down in 3-4 rounds at lvl 50 or so.