As far as positive ROI - I'd like feedback on the following items:-Switching to tankless hot water heater (current water heater doesn't look so hot)-Upgrading electric panel to a Span Smart Panel.

It looks like they are there to reinforce the decking, but there are no joist hangers or cement footings (down to frost depth).For me...I would have a structural engineer come out and evaluate the footings of the buildings to ensure it's sound.Good luck in your search!

This will cover the unit’s condition, including plumbing, electrical systems, and any visible structural issues.

You might be able to erect a shed style place for that, but that's minus insulation, electric, plumbing, finishes, furnishing etc etc etc.. $3k is fantasy land. 

Here's a profile of a builder and civil engineer "Doctor Hemphouse" who has built 60 homes with hemp: https://www.hempbuildmag.com/h... 

There were maybe a handful of us that were engineers that went to ask questions after the pitch.

Lots were sending non-engineers to the property and an engineer was signing off on the report.

Ordering a full topographical survey of the property (which will be required for future development and application processes anyway) will give you the ability to show engineering/design groups what you have, and they can give thoughts and bids leading to a site plan. 

On one of my units the property has shared electric with another unit I own.

Only 10,000 are electric vehicles.EVs are only affordable with heavy subsidies, and even then there is good evidence that they cost more for the user, the environment, and society in general.Just wait until the electric grid collapses.