The market right now is cooling, and I'd say is on your side.

But is it still possible to put a sub meter like device on individual units just so I know who may be running a bitcoin operation so I can send notices to the right units in that event?

Ring cameras, Minut device, a good cleaner, and smartlock activity log on the app, is your best friend for remote managing.

My first thought was ditching the unit and adding 4 mini splits with heat/cool.

You will need to open the files on a computer and, if so desired, transfer that information to your device, either using your device cable or by emailing yourself the unzipped file and opening the file on your device. 

It’s all integrated and easy to manage from PC or mobile device.

You can use his/her name and address or set up a P.O box in your friends name (if they're cool with that) for your mail to go to.

A cool feature on VRBO has been the allowance of a video for each property. 

Your job as a merchant mariner sounds really interesting, and it's cool that you're interested in real estate investing when you're not working.Excited to see where your journey takes you!

Cool thing with private money you can structure it like you want.