For flipping, I'm concentrating on SC and IN.

Fireplaces can add to the value of your rental if they are well maintained and managed.

One time, I sent a letter to an heir in Austin, and thier family ended up selling me a property they couldn’t maintain.

I maintain even break even on valuation (which is rare in SF Zoned areas), the ADU has big disadvantages versus new property acquisition including financing, level of effort, rent control, prop tax being based on cost rather than value added, length of time including length of time from first expenditures to first income, reduction of something from existing unit (in your case existing home lost its garage).Did you see starting next year Mf can add an ADU per unit up to 8 units without any affordable housing concessions?

Even then, you can expect they won't be able to maintain the home to the same level you did while living in it.

What is the appropriate level of cleanliness to maintain during project work?

All are on separate 800 square foot floors, with front and back door egress, well maintained and gut renovations were completed in 2019.      

I would like to concentrate on OTC liens and deed.

This allows you to invest in another property while maintaining the asset.Alternatively, a 1031 exchange lets you defer capital gains taxes by reinvesting in higher-yielding or diversified properties. 1031 has limitations.

I want to make the best decision while honoring my agreements and maintaining professional integrity in this deal.