I would probably go with a HELOC as you won't have to pay for what you're not using unless you've got a specific property you're going to be buying with that money so you know you won't just take out the loan and sit on it paying interest all the while. 

That was the only production schedule I was given even though I specifically earmarked the buildings I was purchasing in the project.

When I call the most seasoned person Allan Howell he gives me great info but doesnt know the specifics. yet you call others and they know it like the back of their hand.I have learned a lot from this process and am grateful for so many members commenting on my posts and helping me learn more about being an investor.

This specific deal was a close friend's apartment that he was renting.

Most of the other posts provided general information that is good to know but did not answer the specific question. 

With the massive increase in STR properties in the US, I am hopeful that lenders and appraisers will evolve to apply income/exp metrics to STR deals specifically, on top of generic property comps.

As a builder/investor myself some of your estimates seemed a little off to me, but those can be very market specific so its hard to say. 

In most states, Airbnb rules are city and county specific.

DSCR loans are a great option for investors looking to scale their portfolio as they are property specific and allow you to close in an LLC

As mentioned above, they specifically allow this.