I like that you included a protective shield for the outdoor sensor, and a " protection" plan for the unit.
I installed the outdoor unit, but I was not impressed by the single screw holder slit in the rear. I think you should have at least 2 points of attachment. I am concerned that a stiff wind will take this thing down someday. A French cleat is one idea, but remember, this thing is plastic, and it will break. I think you should have two " eyehole" projections from the top, rear of the unit, for screw attachment.