If you don't have any debt, a 750+ credit score, and income, you should not have any issues being approved for a mortgage. 

If your goal is to maximize rental income, adding a bedroom or bathroom often achieves that.

They have to be low-income, usually have kids, low education and if they work - a crappy job.

STRs can offer high rental income and flexibility, but they come with management responsibilities, regulatory challenges, and market fluctuations.

It depends on the type of loan, loan to value, fico, income, debt, and experience. 

I wasn’t sure what I need to do to be able to take my 1099 income and right it off with my long and mid term rentals?

Also, focus on 2 years of job/income stability.Class D Properties:Cashflow vs Appreciation: Typically, all cashflow with zero or negative relative rent & value appreciationVacancy Est: 20%+ should be used to cover nonpayment, evictions & damages.Tenant Pool: majority will have FICO scores under 560, little to no good tradelines, lots of collections & chargeoffs, recent evictions.

I only received verbal information on annual income and credit score of the tenant.

This way, you can have passive income coming in from multiple properties regardless of where you are living at the time.Ultimately, the best strategy for you will depend on your long-term goals, risk tolerance, and level of involvement you want in managing the properties.

Rates vary for commercial loans, your amortization might also be different - it depends on the bank though, but the appraisal and value of the building depends mostly on the operating income rather than comps.