Power switch using a lower rated switch
You cannot manipulate the gate control of the LM74610 such that the mosfet will not conduct, because the body diode of the mosfet will always be conducting (in case of correct polarity).

You need the apply a second mosfet to switch on the circuit: either like you suggested or e.g. using mosfets back-to-back and e.g. the LTC4359 as alternative for the LM74610.