How much the pitch (horizontal orientation) can differ from the angle of attack?
270 degrees appears to be the maximum angle that the pitch attitude can differ from the angle-of-attack.
Some examples of extreme differences between pitch attitude and angle-of-attack:
Jet fighter or aerobatic airplane or aerobatic glider in a prolonged vertical climb. (May be a steady-state situation or the aircraft may even be gaining airspeed or it may just be a "zoom" climb where airspeed is exchanged for altitude; obviously only the latter is possible with the glider.) For simplicity assume a symmetrical airfoil. Pitch attitude is 90 degrees, angle-of-attack is zero degrees, for a difference of 90 degrees.
Now the throttle (if present) is pulled back to drop the engine power to zero, but the nose is kept pointing straight up until the aircraft starts to tailslide backwards. Pitch attitude is still 90 degrees, but angle-of-attack is now 180 degrees, for a difference of 90 degrees.
Now imagine the tailsliding aircraft experiences a slight variation in angle-of-attack-- perhaps due to a horizontal wind gust striking the aircraft-- that changes the direction of the relative airflow by one degree, so that the relative airflow is aimed slightly toward the top surface of the wing, rather than aimed directly at the trailing edge. Now the angle-of-attack has changed from 180 degrees (which also could be called minus 180 degrees) to minus 179 degrees. Now the difference between angle-of-attack and pitch attitude is 269 degrees.
Flat spin with flight path approximating a vertical descent. Angle-of-attack may be close to 90 degrees, but pitch attitude may be close to zero degrees. Actually on the retreating wing it would seem the angle-of-attack may go beyond 90 degrees (wing actually moving backwards relative to the airmass, so the local airflow comes partly from behind), in which case the difference between angle-of-attack of that wing, and pitch attitude of the aircraft, would also go beyond 90 degrees.