Mage AoE and friendly fire HELP

well, so i want to be a mage and to use the fire tree...because fire is cool lol
however, all the fire spells are AoE and do friendly fire damage

since i will have one warrior, my question is how can i avoid killing my team?
one obvious solution is to try to move my team away from the enemy but this is for obvious reasons impractical

force field is an option but i need to use 4 skill points to get to it and i don't want the other spells...

are there ways to make charachters in my party, say, resistant to fire?
or perhaps protect them from damage?


also, are there penalties for party members who die?

will i lose anything if i kill one of my teammates?