The interest rate on a HELOC or Heloan may be better than the personal loan. 

The LTV of the loans I’d conservatively gauge at about 35 percent.

Kieran, the best bet here is to refinance with a DSCR loan.

If my spouse wasn’t opposed to moving I would try to buy a new house hack every 12-15 months and use low down payment owner occupied loans for as long as it made sense.

If it is someone you know you can give them a straight return as if its a loan - can provide a lower interest rate to provide upside - it really depends on the lender and what are they concerned with and what is their risk profile. 

So i put in an offer for 10% down conventional loan, $530,000 with 10k back to me for closing costs and it was accepted right away.

SubTo is taking over someone elses loan.

I might have a private lender referral that does rural loans in Mid-MO if you're interested. 

Pay Down the Loan Faster:I’m considering applying $40,000 annually to the loan principal.

Fannie/Freddie (Conventional) loans aren't just about rate and transfer taxes.