Sorry so late to the party, overate T-day and lazy, so sorry haven't parsed just skimmed, couple hot takes.
OP says no belts, means direct coupled, to me that means EcoTech, only one that outputs big amps at such low
rpm, plus simplicity. Run
watermaker, biggest
inverter loads like
laundry, maybe holding plate
charging at the same time.
7 kW of torque will require more than 12HP.
Ask the EcoTech guy for reco's.
If a good HD serpentine setup I doubt belts a problem myself. In which case can run two 2 alts for redundancy and low sideload, can still go EcoTech, not *that* big a deal to ship for repair/exchange if one goes south. But other alts like that 400A Humvee for $500 or a stock LN is now possible
Watermaker and holding plates can also be direct driven rather than
electric.