Depends on the amount of drywall repair but those prices seem about right for this area on turns. 

Said differently, you won't need a special ADU permit to create an ADU.I'm interested in potentially purchasing a single-family home in eastern MA (Norfolk or Middlesex county), and doing this exactly.

Interest rates decreasing a little more will be necessary to make this possible, too (DSCR loan).Also I will have another deal refinanced by then and gain about $70,000 of capital from refinancing that.

Start by reading the Ultimate Real Estate Investing Guide: https://www.biggerpockets.com/guides/ultimate-real-estate-investing-guide/introduction2.

What market are you currently in, and why no interest?

That’s how the buyers have been paying for their own realtor and then paying bank interest on the commission, while the bank financed an inflated price. 

Gardening maintenance: This would also be capitalized, as it was necessary to get the property ready for tenants.3.

This would be my first investment property.

Does anyone have any actual data on this? 

Even on Sparefoot they will always outrank you.If you do this, ask for a Construction loan with interest only.