If they can’t afford the same standard of living they will be reluctant to sell, even if they have considerable equity in their home.

Some title companies might assist in this process, but it's best to check directly with yours.

How can I check to see if the unit is illegal not?

Check Your Area’s Water Level: Often overlooked, especially by new investors unfamiliar with septic systems, the effectiveness of a septic system hinges on its leach fields.

Check with your county tax assessor. 

Please check out this recently published article on BIggerPockets which addresses your exact question - BRRRR financing pros/cons of all the options (Cash / Hard Money / DSCR / refinance options)https://www.biggerpockets.com/blog/brrrr-loans-what-are-the-...

NY isn't TN so you need to do your research and check the comps.If you acquire it, you'd have an option to flip it, develop it or live on it.  

This is so that the lender may demand full repayment if a property with a mortgage is transferred into an LLC and a due-on-sale provision is triggered.Before putting the property into an LLC, make sure to check with your mortgage lender.

You can also check meetup.com or search facebook for real estate investment groups, clubs, or meetings in your area.

My taxable income is actually so low in 2023 that if I take the $25k special allowance deduction for passive losses and the regular standard IRS deduction, my taxable income is negative.