A possible idea for a unique combat medic, field ops and engineer.
Heli or Helios would serve a similar purpose to Skyhammer, but instead would throw a smoke grenade, red for an enemy, blue for a friendly, the grenade if indoors would fog up the room, letting only the possibility of a Redeye to look in or our, but when throne outdoors a medium sized attack shopper with turrets on it would hover over, firing at enemies visible to it until it is destroyed or recalled, if players are dead while its called in they can spawn from the chopper, rappelling or simply jumping off for no damage, maybe even mounting the turrets.
Medi would serve a similar purpose, creating a foward spawn for his/her teammates, with the possibility of it being a very loud computer station similar to say the large ammo crates visible around, but can take a beating.
Ratchet would serve as a different engineer, yes they can arm and disarm c4 as fast as other engineers but instead drop Tune-Up cases, these would increase many stats on their teammates weapons, making said teammate be very loud and visible somehow, like say a a golden hue to them.
All I could really imagine is Heli wearing some sort of helicopter pilot gear but rather different to pheonix, medi appearing like a tall labcoat clad medic similar to aura but with q lot of armor on over said futuristic lab coat and Ratchet looking more or less like a trucker/mechanic.