My favorite Squad:
Two Assault/Heavy, abilities RC, RB, War Cry , never Rally, endgame mounted weapons + Neural Torso
Two Heavy/Assault , abilities RB, War Cry, Boom Blast, never Rally or RC , mounted weapons
Two Sniper/Heavy , abilities War Cry, Inspire, but not RB
And one Technician , deploying/using turrets, healing and recovering body parts. Electric reinforcement never unlocked
This squad is enough for Citadels, special missions, whatever
And for those missions those two soldiers using RC (not every turn) can deal with lot of enemies, even hidden inside buildings