Ailerons can have as many servos as you want. If one servo then typically the ailerons have torque rods. Torque rods are a wire with a 90 degree bend at each end. The two bends are 90 degrees to each other as well.

In case you aren't aware, ailerons move in opposite directions to make the plane bank.

Another way is to have bellcranks in the wing that are connect by pushrod to the servo and the control surface. Don't see that much any more because most people would put a servo out in each wing for a tighter setup.

By backward, I meant I may have channels 3 and 4 confused as to what they do. In other words, 3 may be throttle and 4 may be rudder. I can never remember. I just plug in servos until the right one moves when I move the stick.