[1] How are retirees living on rental income supposed to pay their mortgages?

If you sell property 1 you’re basically paying off a 3% mortgage.

Sharing our home a bit has been a small trade-off for living nearly mortgage-free while building wealth.

Suppose you have $46,000 mortgage at 8% interest on restaurant, $22,900 SBA loan, $3,900 at 1.75% interest on a microloan, $23,00 on temporary 0% interest credit cards all for the same business totaling $95,000 in debt. 

FHA rates are actually lower than conventional right now even though there is a monthly mortgage insurance it’s not much in most cases.

Many banks handling tax escrow accounts for mortgages have mistakenly thought there was one tax due twice/year or totally missed one of the taxes.Investors should research the SEV and the Non-Homestead property tax millage rates to project what the property taxes will be after adjustment.

I have just over $200K left of owner-financing, but I'd like to obtain a cash-out mortgage/loan of $500K (ideally) to be able to pay off the previous owner and make some repairs, etc. 

Your anonymity is blown if you as manager/member of your WY LLC sign a mortgage ... i.e. get a loan.If you own property in a revocable trust (land trust) with someone other than yourself as trustee you can achieve anonymity, since that trustee will sign the mortgage.

I would say generally, buying already built is cheaper on the mind, stress and time.

Where I live for the cost of doing so it is cheaper to buy new multi family 2-4 units and then earn 3X-4X the rents for the same cost.