If the insulation on the wires looks like cloth impregnated with black tar it is past it's service life. 

On the resale' an appraisal gives a value of 40-45k for an ADU, versus a duplex conversion you will get full value of each square foot.

*Full disclosure YES I am an investor with holdings in "O". 

Hey Suraj, I moved to Columbus a few years ago (from Portland, Oregon which was super expensive) to become a full time real estate investor, and ever since, I've completed quite a lot of BRRRRs, flips, and own a successful rental portfolio here in Columbus Ohio.

today I still have my lending bizz full throttle..

Will this be your full time job?

A fairly common way that self-managing landlords handle this is to create a company that provides services to your properties.

The lease he signs if done will meet the debt service on the loan or I wont make the deal.

It appears if it wasn't under an LLC, it would get a full step up in cost basis at date of death.

Once you get hit with a $675 to $750 HOA the NOI will become more of a debt service coverage.I would sell and if you get hit with a tax just 1031 Exchange it into the new purchase.