That should reduce what I'm currently paying by almost half, and allow me to save money faster so I can parlay that into a fund for a second property down payment.

New always sells better and faster.

Couple questions:1 - one of the biggest "regrets" posted is that people didn't scale faster. 

(I know 0 down and 0 interest sounds outrageous, but beyond that please consider my specific question that follows) my specific question is this: if I pay my mortgage with her off faster than she pays her loans off, how would I go about helping her payoff the rest of her loan amounts.

(will the house sell faster if it has a tear off roof?)

Having a reliable PM who is familiar with the area is worth its weight on gold in these situations (as an out of state investor).

You can get a rental or sfr and rent out and get cash flow and ride the appreciation much faster and higher [ percentage wise].

But then maybe yours will rent faster and people will stay longer because you spend an extra $200. 

You need to put as much as you can into that mortgage or your accounts as fast as you can so you can scale faster.

Anything that makes the property more appealing will result in a happier tenant and will cause it to rent faster in the future.The difficult conversations come when the tenants idea of "appealing" and mine are different.