The Apache has a 30mm chain gun. It carries Hellfire (anti armor), Stinger/Sidewinder (air to air) and Hydra (air to ground, APKWS guidance package available) missiles.
The Warthog has a 30mm gatling gun. It carries Maverick (30cm air to ground including armor), Hydra (70mm air to ground) and Sidewinder missiles, plus a variety of bombs.
The Warthog seems to have a more capable and complex weapons load, so why doesn't it use a separate gunner like the Apache?
The ULB (Unmanned Little Bird) version of the AH6 can fly with two, one, or zero pilots, so it seems that helicopters can be automated like fixed wing aircraft. source
The Kiowa Warrior 50cal machine gun was not turret mounted; it was fixed to the airframe like the A10, though not buried in it. This is used in an armed recon role, not attack.