FHA loan through my mortgage broker associates.

Doing a 75% 1st mortgage and 15% heloc or heloan would likely give you better cost of funds all around.If this is an investment property, you can do 80% cash out refi using NonQM loans such as DSCR loans, but at a higher cost/rate than if you stick with 75% loan to value. 

A lot of the owner occupy loans require you to live there for at least a year, so it's not forever. 

Make sure you talk to a Banker or Loan officer that is well versed in both SE (Self Employed) income and also Non/QM programs.One tip I will give you as a Banker is open up a "Business Checking account" and for the next 12 months pay "Everything" out of that account. 

And your point about a lingering HM loan makes sense.

So when the bank requires insurance for the loan amount.. that will work generally.. 

You typically need up to two years of stable employment before a bank will loan to you.

I would get an attorney or title company involved to create your loan documents to ensure they comply with the law and cover all the aspects you need.Another method that is likely your best bet to take on investors is to create a joint venture (JV).

(Insurance, Loans, Zoning, STR, ADU's, ??

Also, I am guessing that due to the state of the house, it would not qualify for a conventional loan?