There's already a four motor version around somewhere that does not need a tail rotor. Two of the motors spin the opposite way and have reverse pitch rotors. I've seen one of these fly and it does very well. Pitch and roll is handled by just throttleing pairs on one side or one end and yaw is handled by increasing power to the clockwise pair and reducing it to the anti clockwise pair or vice versa.

Your version may need a tail rotor since there's only three motors but there's no reason it can't perform the rest of the stuff using the correct mixing ratios to the throttles.