On the issue of summons, you can't summon before the square starts, but you CAN summon after the rest of your party are off screwing around

. I beat the squares with a fighter4/cleric, and having 6 greater drowned ones really helped (great strength on them, and even better resistences)
If you have a good warrior/cleric, I'd recomend them over a paladin for summons and the Heal spell, and since they can re-buff themselves. It is your choice what you want to do.