Permanent wire to a WP box, Then cord and strain relief- perhaps 18"- with a WP female cap- then plugged into a male rec. located in (depending on room-have not seen the controller as of yet-)the bottom- or a suitable WP enclosure.
In and out for a whopping $400.00 +- as opposed to a Grand for a generator interface set up.
First, the pumps seem just a tad large for a home. Maybe there's a significant lift or something.
Otherwise ... is it really a requirement for a generator hook-up? Or just a requirement for back-up power?
I ask because I have seen pre-packaged battery systems for such pumps. Set on the floor near the pumps - plug pumps into the unit - plug the unit into house power - done. Might be worth a visit to the plumbing house.
Alan, the 'grinder' is a perforated plate in the intake of the pump. A knife spins across this plate. The device is intended to cut up stringy material -think paper towels and sanitary napkins- before it enters the pump.
Pumps have trouble handling stringy materials, as they tend to wrap themselves around the shaft - eventually binding the pump.
I like your original idea. There's no getting away from some use of cords; the pumps and floats have cords, and a portable gennerator will tie in with a cord. There's no way to switch power supplies that is more idiot-proof than having the guy actually move the plug.