Sites like SmartMove are easier since the applicant will verify online and it is a soft inquiry on their credit.  

Once you get a good idea of the number of units you can develop, you can estimate their potential sales revenue, back out hard and soft construction costs, back out an acceptable profit, and that will give you and estimate of the site's max value.

If so, I'd rather just pay the 10% and use my 10 "soft loans" for other properties.

I spent about six months researching the area and the options, making about 40 offers (some of which ended up going for 100k over list), and looking for a "deal;" the prices went high enough that I nearly threw in the towel, but my numbers, discussion with current owners, and observation of traffic and occupancy over that time seemed to still point to a robust STR market.

Meaning if anything changes like credit score, late payment, home value, accidental credit issue like over credit card limit high balances, excessive trade lines the institution does a soft pull every month and can decrease or close the HELOC limit.Based on actual numbers most people end up consolidating the HELOC into their home down the road majority of the time.

She fully furnished her house with everything down to towels, linens, flatware, and lifestyle appliances (blender, grill, etc...).

You can run the risk of fighting the tenant and going to court which is likely to well exceed the cost of rent you would receive as well as the mental capacity you've already spent on this issue if you lose (which by this thread most are in agreement that you are on the losing side) You'd also lose the tenant and have to make necessary repairs, marketing, and showings for the next tenant. 

There are some turnkey companies out their that write super soft leases to get people in to the units and then sell them off.

Yes on wear and tear, and the CS market is pretty soft right now.

I have 4 dogs myself so I have a soft spot when it comes to renting to people with dogs.