Having never flown a canard equipped aircraft I do not know what AOA can be achieved with good directional stability.

I have read that 45+ deg AOA is not uncommon with real aircraft.

Yes… concerning your stall AOA question & that ties back to the proximity of the powerplant to the airframe/flight surface.
Just as the tractor powerplant can delay stall at the canard I would speculate the pusher has the ability to delay/reattach/redirect flow for a lack of better words the turbulent flow on the main wing.

I would speculate your suggestion of installing a rudder below the wing would be somewhat helpful