Assuming this does leave you with enough reserves needed for the unknown.  

My advice would be to purchase a more stable option without the high turnover and unknowns of a STR for your first investment property and then diversify once you have some cash flow coming in and your property has appreciated.  

Much better than looking for an unknown stranger to partner with.

There are always many unknown factors but I will tell you my most recent property was a bank owned rental property they tried to rent it for $2,000 then dropped as low as $1,750 but when I purchased it I had multiple section 8 parties interested at $2,100.

Big unknown about rates and terms that will be out there in three years.PITI today would be about $5800 so your proposed rents sound good, but unknown if accurate what will the square footage of the units be when complete?

Considering it's still relatively unknown, I think we have a while before that happens.Everything that was "trendy" at one point still works.

It was more of a general example of unknowns I will encounter in transitioning my primary to a rental property.

- unknown by what you saidIf your middle FICO is 721 which probably it is as you got a large HELOC yes this could work as a conventional loan.If you show losses as net numbers, well unknown.Other option is to apply for DSCR - MOST do not use short term rental income to qualify you need a market survey of the long term rents to fully cover the PITI+HOA - consider HOA in Florida starts at $400- 900 you will need 30% down but no IRS returns needed but rates are a bit higher and cost to not have a prepay is in the $8500- $12000 range, cough cough.DSCR: $600000 sales price with 20% down PITI is about $5250+ HOA and HO6 insurance 700= $5950  the problem is finding a condo that can rent for $6000 long term will be very hard. 

I should say it's normal to get afraid when you are buying your first house - it's a massive financial decision - but it's also normal that you should probe that fear and understand if it's just the fear of the unknown or your instincts telling you that you're making a mistake.

Also, be careful regarding the "unknown/recommend further inspection" noted in termite reports as unless your agent is very thorough, can also maybe gloss over those items which can also impact your bottom line.