Deep Cover works great with an Overwatch build, because it will activate Hunker Down automatically if you Overwatch. Aim perk will then buff the accuracy of the Overwatch shot.

Waylay is often misunderstood. Normally Overwatch grants exactly one 1 shot. With Waylay, you get as many shots as the number of Action Points of any kind you have when you use Overwatch. So if you use Overwatch as your last action, Waylay does nothing.

But if you get a Move-only AP, and a regular AP, and then use Overwatch, you will get 2 shots.

• Grapple Gun - use a grapple gun to move around. Purely cosmetic difference from other grapple abilities. You can also use the Grapple Gun to collect loot remotely.
  
• Resupply Ammo - throw a spare magazine to a nearby ally so they can reload their weapon for free. If Keeper carries Experimental Ammo, its effects will transfer to the targeted ally until their next reload. If the target soldier already has Experimental Ammo, its effects will be termporarily overridden.
  
• Bandage Throw - throw bandages to a target ally so they can heal over time and stop bleeding. Ally has to be conscious and not impaired. Can be used on yourself. By default heals for 3 HP over 3 turns, has 4 charges and can be used once per turn.
  
• Supply Run - using Resupply Ammo or Bandage Throw on an ally grants Keeper a Move-only action.
  
• Reposition - use the Grapple Gun to pull an allied unit towards yourself, preferring tiles in cover. Ally has to be conscious and not impaired.