I'm on the last stretch trying to level up characters, some of whom aren't even at 50. I've only got half through the Arena and it is unlikely any more will get through at present. There are other combos/spells to share as well but they aren't high enough. The lava pool is tedious and expensive. Is there a way of getting back underwater and fighting the crystal zoopoos?
Instead of the lava pool, put Tara in your party, select fight instead and do the hard one. Lava Wall wipes them out in one go, it's free and you get bonus XP for everyone at the end of each round! Plus, 21 gold add up after awhile.