One or two PVs for multiple houses / structures?

I would say seperate PV will be easier for troubleshooting and maintenance. If you got one PV for 2 or more houses and they are far away from each other, when some parts of the system are faulty, for example, it will take you a lot of time to check them from one place to another.

I would expect you would figure the needs of each building and
then see how the Solar output would feed to the grid with net
metering. I use direct burial cable to connect it all. Because the
solar runs continuous high power for many hours a day, that run
might be calculated to hold down IR losses to around 2%. Other
buildings might tolerate more peak loss, rarely attained. Some
of my postings here show how 4/0 aluminum triplex (equals 2/0
copper at 1/5 the price) was used to do this over distance.

A ground mount panel array has many advantages, I have a list of
52 reasons. Location for best sun (least shading) might be the first
consideration, then minimize wiring losses. A series arrangement
of panels will operate at maximum voltage, minimizing losses and
wire required compared to a micro converter setup, and is cheaper.

Check regulations too, less on a ground mount.
good luck, Bruce Roe

Thank you! The place these are going (HI) unfortunately does not have net metering anymore. It was supposedly phased out for new customers. Might come back at some point. As far as mounting, ground mount sounds pretty good. One of the building does have a standing seam roof but I am looking at a carport like ground mount that might work even better.