I've identified one property that we will likely officially "identify" in the 1031. 

I believe it's a $100 application fee.https://sos.nh.gov/corporation-ucc-securities/corporation/forms-and-fees/domestic-and-foreign-limited-liability-company/domestic-forms/

I don’t know if I should try to secure a HELOC as soon as possible or wait until I’ve been able to save up more of a cushion in cash.

But they didn't report anything about the door damage at that time and also never mentioned about it before this pre-move out walk through.In this case, do you think I can deduct the cost to fix this damage from their security deposit?

So you should remember that reasonable wear and tear is NOT damages and may not be offset by the security deposit.

Instead, make sure to prioritize the security deposit and use discretion in choosing renters.

I'd focus on areas that already have ordinances that officially allow them, like Wheat Ridge, Arvada, Littleton/Highlands Ranch, Jefferson County, many mountain/ski towns, etc. or just go with medium-term instead of short term. 

Of course, set your rent and security deposit figuring this. 

I will have a separate bank account for the LLC, and I have separate accounts for the rent, security deposits and cash to pay for expenses for the property.

I haven't officially put any of it in to practice, found another niche I like a little better for now (land).