Loadout:
Any Primary Weapon (but not Templar Gauntlets)
Pistol or Sword

Squaddie:
Charge! (Dash up to an enemy and attack them with your sidearm)
Snapshot (after moving you can shoot with sniper rifles but at an aim & crit penalty)
Fire Pistol
Slice (A sword attack that can be made for 1 action against adjacent enemies)

Corporal:
Sidearm Specialist (+1 dmg with sidearms)
Implacable

Sergeant:
Shadowstep
Hunters Instincts (Do +1 dmg against flanked targets & get 10% crit chance with swords)

Lieutenant:
Weapon Specialist (+1 dmg with primary weapons)
Deadeye

Captain:
Deep Cover
Untouchable

Major:
Weapon Expert (+2 dmg with Primary weapons)
Seek and Destroy (50% chance to take shots at newly revealed enemies)

Colonel:
Rupture
Rapid Fire

GTS:
Conceal & Carry (gives a smaller detection radius when concealed and remains concealed when the squad is revealed)