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.  

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

Debt will get paid down, rents historically will go up, and values historically will appreciate. 

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? 

no debt? 

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?

But if you're able to figure it out and get it built, you can rent out the units and essentially BRRRR it and pull some/all of your equity out to repay your debts, yourself, and potentially keep the investment cycle going. 

If the bank prices their debt based on the fed rate you typically see WSJ Prime + 1%.

I as a lender as part of settlement had our servicer unwind some negative reporting.As a sidenote I saw a post online somewhere else where someone who had an owner occupied home for several years relocated for work and teh servicer sent a letter telling them they are not in compliance with their loan because it must be owner occupied for the entirety of the loan even though the loan docs say one year....Again, servicer overstepping their bounds