However, it takes a long time to pay off this property and forces me to accumulate much more interest over time.

So newbie question - you basically have to get your GC (if you use one) to come to every potential site and ask for an estimate?

Depends on the bank, some due a lower LTV and get you a HELOC with no site visit and others do a site visit with higher LTV.

However, I feel that paying off the mortgage is a safer route for me.

They make LOTS of money for the company because they pay out much less than you pay them!

(this would cover my half of the rentals mortgage)-Move and use my equity to pay 100% of the rental mortgage and use the rest towards my personal house?

The roof leaks and has to be repaired by the time the rain comes and there's no heating or AC units.The partner’s focus on finishing the project to perfection rather than timely completion has further delayed progress, and our financial situation has worsened as we struggle to pay the mortgage.Given these circumstances, we’re considering selling the property.

Searched four sites and came up with a different decision than your original decision to go with them. 

Rates are a measurement of risk for the lender and there are some people who cash out and stop paying the mortgage.

We allow guests to pay 50% at time of booking on the Airbnb platform.