Turns out, during title search, they found a HELOC with a $9k balance...and she actually owed $112k not $98k. 

You need a compelling balance sheet reason as to why you plan on fulfilling the lease, BUT can't have the guarantee on your BS.

So overall good balance sheets at both consumer and bank.

This may involve you paying the balance, or just reinstating payments in your name - that's why I say it depends.

We're still in the midst of a very strong sellers market, but with the onset of COVID-19, we are starting to see more inventory hit the market (time will tell if the increased inventory will balance out the demand).

The principal portion of your mortgage payment simply serves to reduce your existing loan balance.

It's a balance!

Will the unpaid debt balance at the time of the sales be deducted from my % share of the proceeds including the original principal? 

The STR landscape changes frequently with many cities tightening restrictions but there are opportunities depending on what your looking for.La Quinta for example, has a 90 day moratorium on any new STR permits as they look into their STR and balancing recent neighborhood complaints due to the increase in demand for STR due to the pandemic.

as stated above a snap shot of your current balance on your statement with number redakted works 99% of the time.Other wise just get a stock letter.. thats what i have..