Additionally, since my parents are nearing the retirement age, I'd like to prioritize low-debt, high-cashflow deals.

Two main reasons being: (1) debt does not increase your basis in an S Corp, which means your losses get limited.

A HELOC is a short term debt instrument.

If you do have enough other income then you dont even need to lease out this property to start your refinance.However if you dont have enough income to qualify with no rental income offset then yes you will need to obtain your lease(s) and security deposit + 1st months rents deposited before you can utilize 75% of this gross income - your monthly PITIA payment (in terms of qualification on this property refinance.So all in all Id make sure what your current debt to income position is first of all (DTI) and then strategize to see if you even need the leases at all.

What doesn’t work today may work in the future.Another challenge with the traditional BRRRR model is the resulting high debt load often isn’t fully covered by rental income, especially in today’s high-rate environment.

We’re trying to invest with a long term mindset with as little debt as possible.

Refi after construction.These numbers consider only the portion of costs of the HEL attributable to the land purchase, not the payoff of the HELOC (which we took out to buy the Seaside condo).Cash In:                     $66,166 (Cash, 1 year of debt service of HEL, debt service of const. loan, furnishing)Amount Financed:      $548,000 (home equity loan + construction loan + closing costs)Total Cost of build:     $614,166ARV:                               $850,000 (or rather "after construction value")Refi                                $637,500 (75% of value + closing costs)                                        Cash Out                       $89,500New payment             $4500/month (54,000/year)Estimated Cash Flow (pre-tax numbers, so actual mileage may vary)airBNB year 1:            $70,000     (net income $16,000)airBNB year 2:            $100,000   (net income $46,000)airBNB year3+:           $120,000   (net income $66,000)ROI (construction year):    0ROI Year 1 of STR:              24.2% ROI Year 2 of STR:              69.5% ROI Year 3+ of STR:            99.7% Did I calculate these ROI numbers right? 

That all makes sense to me but it makes me wonder how can you be "financially free" or even just start building wealth if you are 100's of thousands of dollars in debt at all times.

Do DSCR loans qualify if purchasing through 1031 w/debt-carry-forward requirements?

Purchasing subject to allows you to (1) buy a property and pay a lower rate (3-4%) that was in existence when the loan was originated, so cash flow will be better as well as equity buildup; (2) not have to qualify for the mortgage saving time, expense, and allowing property purchases in greater number than otherwise and (3) no personal liability on downside (4) no debt added to your PFS.