I don’t understand why you would put in something other than the FP?
The boat was designed for it, and with reasonable maintenance if performs beautifully.
also, the gas water separator & sound shield make this silent running when you’re in the cockpit,
The genset was sized for all 3 airco units running plus charger / inverter.
Going to a unit of half the output doesn’t sound like a good plan.
The FP unit isn’t inexpensive, but it’s a high quality genset