Jon, your 1400 should drive M80s very well, and at the regular 8 ohm setting without having to use a lower impedance setting which would limit the voltage and therefore current and power available. Connecting M22s in parallel with them might well cause a problem; the resulting net impedance for paralleled 8 ohm and 4 ohm loads is 2.67 ohms(1/8+1/4=3/8, or 2.67 ohms). Besides that, running two different(even if similar)sets of speakers simultaneously on the same material would tend to muddle the sound.
