It's truly the best option for your scenario for the best long term outcome, and the other options aren't close.Best of luck!

Most new finishes will last for a little bit, but given many tenants are hard on things, it won't last long.

I've included a preliminary floorplan below.My goal with this ADU is flexibility in terms of renting it out either short-, medium- or long-term rental in the future for income, as well as maximizing resale value (main property is 1300 sq ft 3/2) to someone probably with an investor mindset who would want to house hack.My main concern is whether it's a good idea to have 3 en-suites at the expense of having a small living room/kitchen area.

They are in a year-long lease which ends 7/31. 

Hello -I live in Long Island, New York.I am exploring STR investments perhaps in markets near New York.Just having a very hard time starting off.

These contracts run from 3 - 5 years; is there a downside to skipping recording until deed is ready to go to the borrower, as long as I'm staying on top of taxes?

Refinance in to conventional loan as a primary for good long term debt.

You may not get 100% economic benefit, but you'll earn a ton in experience and build up your track record.Think of the long game, and don't get stuck on the economics of a partnership.

Housing is a necessity so as long as you are in a decent area for rentals it will rent, but it will come down to price.

If your area is anything like mine, you can probably reach out and find a half dozen older guys who have done this for so long that evicting a loud felon is no big deal.