Typically the hard money element in an initial BRRRR is to cover a cash shortfall between your own cash on hand and the cash position a mortgage lender requires. 

The math doesn't work for long-term rentals though for the same property.After initial research, my search was severely limited by city zoning prohibiting short-term rentals in many oceanfront areas but there are still some options left.I'm looking for opinions of skilled investors here about short-term rentals with Airbnb/VRBO.

If you do decide to take that risk, a good way to keep costs low initially is to consider new(er) construction.

The initial plan was to renovate as vacancies became available. 

@Dillon DembowskiCongrats for taking the initiative so young - your goals are not too lofty at all.1.

My team and I walked away with some very valuable knowledge and experience, as well as doubled our initial monetary investment.

Well I think the good news is the refi from the deal itself is going to take its rental income into account for the DTI calculation, while DTI from the initial HELOC will not. 

My initial rent analysis for the area we prefer to invest in shows rents around $900k-$1400 for a 1/1 unit, depending on updates and size of unit. 

I'm looking at developing Area, smaller municipalities with some R-4 Rural (Duplex or Rural Comm) that could be used as a land split to get the initial investment money back rather than trying to force appreciate the home itself and simply Rent at a slight cash flow ($50-100/mnth, $150 is the best I've found on MLS)   There's obviously some serious risk here because the initial $500-$3000 for the application doesn't come back to you, and you could very well be denied depending on exactly what you buy then left with a cash-in property with low returns.

Very experienced investors or people with a lot of construction experience are sometimes comfortable doing their own “inspection” on the initial walkthrough.