Which is still possible to get a negative DSCR loan, but the rates go up a bit for the associated risk!

The house is particularly appealing to me due to the low mortgage rate that he got in 2020.My question is whether I should buy his property "subject to" or add myself to the mortgage/deed.

Typically, I am able to purchase those properties at a discounted price and walk in with built in equity.

Forced Apperception (BRRRR or buying at a discount) allows me to build in equity from the beginning of the investment in case I need to fire sale the property for an unforeseeable reason.Debt-Paydown and Tax-Benefits are just a result of owning real estate and can be more-or-less predicted over a time period.

I am simply asking to include something like, "unit has brought in rents well above market rate year over year" or "unit is cash flow positive". 

What's the accuracy rate?

In April, shopped around a bit with a different agency, but they couldn’t find a cheaper rate.

That amount will have an effect on the premium for that portion of coverage of course, but shouldn’t raise rates on the rest of it. 

The highest insurance rates in the country are in Florida right now, but I still like the state in general.

There is very strong appreciation over the last few years even with the high interest rates.