I beat the EA with the composition:
Warlock
Warlock
Ranger
Rogue (arcane trickster)
No healer, no tank, no problem.
Although rangers can learn a healing spell if they choose. Mine hasn't so far, but at least at low levels you don't really have the tools (other than potions) to heal through damage. In my experience, I'm either controlling the fight and out damaging my opponents or I'm losing big.
