The 'Nook was deliberately designed in, but as you say uncoupling in N seems problematic. My wagon stock is all old Farish/Peco, so presumably any alterations (beyond my dexterity any way) would require total removal of existing Rapidos (?).
You could use the Peco stock for auto uncoupling with little modification actually as Peco produce a purpose made extension to the couplers which actuates magnetically, they also produce electromagnets for them. NR-103 is the part number for the coupler lift arms and PL-25 is the magnet. I doubt you'll be wanting to shunt coaches, but even though it states that they're not suitable for stock which uses springs in the couplings I have seen them used successfully when the springs have been weakened a bit, so one end of a coach which couples to the engine could be tweaked to work.