Running the engine two hours per day to make hot water, cool the frig, and charge the house batteries might do it, with just a bit of supplement from, e.g., solar panels. It would be nice if the alternator were larger, but it isn't...it is what it is! Assume there's an external regulator....if not, you're not likely to get anywhere near 80A out of the alternator for 2 hours per day.
Before you get too fancy, I'd install the larger house battery bank (yes, 800AH should be sufficient) and give it a go for awhile. A good battery monitor, like the Victron, would be helpful to provide good data on your power usage.
Look at ways to reduce your power consumption, e.g., replacing incandescent lights with LEDs.
Re: solar, you might think about two 135-watt solar panels, run in series (to give 34VDC) and a good MPPT controller. In the Caribbean, this would provide a lot of charging current throughout the day, and is virtually maintenance-free. Wind generators require maintenance, can be noisy, and can be a PITA, IMHO.
On a Bendy-toy 50, you guys should have a ball!