full healer squad indeed.
The taunt and crit immunity isn't a good idea. Healer allies already gain stealth whenever they fall below 50% Health. that already helps spread the damage. However you do make a goo point on the damage. Also, in a full healer squad everybody is going to be healing left and right, on top of the heal over time effects. so the "Heal 10% of their max health at the start of their turns" part of the leadership is overkill. I've changed it to "Gain offence equal to 10% of their max health" to help offset the low damage output