Hitec Mighty Mini's are the hot tip for ailerons. Save over half an ounce each side. More torque than standards to boot. (55oz-in torque @ .9oz weight) Only about $21. They're the HS-225BB.

Any brand servos plug into Futaba RXs. It's Futaba servos that don't plug into anything else.

Look at HS-475KB for a standard for rudder or elevator. 60oz-in torque and composite gears (something like 5x stronger than regular nylon). About $16. or $17.