So my first property back in 2001 was made possible with a $78k loan from my parent's LOC. 

As many investors know, lenders typically require more down payment 15-25% and to utilize Debt Service Coverage Ratio or DSCR loans would not allow vacation rental projections or income to be utilized for qualifying purposes.

it's going to be very difficult to cash flow with interest rates where they are, especially if you would be taking out a DSCR loan.

Additionally, we have very unique financing options available to investors through various lenders such as an investment portfolio loans where someone can buy multiple investment properties with as little as 5% down, a 2.99% seller financed loan, new construction loans, etc.

The loan was a normal 20% down mortgage.

Paid cash and would like to refinance this deal using a DSCR loan and continue doing this.

The principal and interest payment will remain the same, but the loan payoff date will be escalated as you make extra payments towards the principal.The details of your monthly payments should be available on your monthly mortgage statement as it lists the principal, interest, taxes/insurance escrow, and PMI paid that month.

I've heard stories of "gurus" promoting courses on how to renovate and lease homes to housing choice voucher recipients and part of their sales pitch is higher loan leverage than market signed leases.

2) If two partners were doing a STR deal, and Partner A is the money partner (puts name on loan, and provides down payment) and Partner B is the active manager.

Investor was able to do a bridge loan and pay for the purchase and the renovations  for about 20% LTC (approx 31K + closing costs down).