United Wholesale Mortgage is only lender I'm aware of that allows for $100k or less for a DSCR loan.

My wife is from a country that does not allow lending or loans to acquire housing.

Mortgage recasting, also known as re-amortization, is a process that allows homeowners to lower their monthly mortgage payments by applying a lump sum toward their principal balance.

If it is good enough for my local building authority to get permitted, it is good enough for me.In both of these cases, it was the presence or absence of the all mighty built in closet that allowed me to execute these real estate maneuvers. 

Living in one unit and renting out the others allows you to deduct 75% of expenses like mortgage interest, property taxes, insurance, and shared repairs as rental expenses, while the remaining 25% applies to personal use.

Hawaiian real estate law differs from other western states significantly, mostly due to its monarchal heritage and the Bishop Trust influence.The basics are the same as would be in California; determine the condition of title ownership (individual(s), estate (including conservatorship, if appropriate) OR fiduciary acting for trust.Use a qualified private money equity lender to make a loan sufficient to buy out the cash-only beneficiaryThe legal community in HI and Big Island in particular is small.

They don't allow auto payments or automatically add late fees, and tenants would have the option to pull their payment back, which is not ideal.

Could be.I think that for most individual American investors leverage is a critical tool. 

Quote from @Anil Shah: Since I read a townhome, I assume there is HOA - do they allow STRs?

Paying off the mortgage can provide peace of mind and simplify retirement, while keeping the debt allows you to leverage your funds for higher returns through investments.