Be aware if their payment is clearly labeled "for rent only" or similar, and in that case, only apply it to rent. 

The main issue I have is contemplating the baloon payment at the end of the 2nd year and refinancing the remainder with a bank...how can I compute that into calculating the IRR?

Now to the bad news: it is REALLY hard to be a 20yo real estate agent and make a living wage, let alone generate cash for a down payment.

DSCR loans are based off of down payment, credit score and either actual or market rents so it helps to supercharge an investor's real estate goals and net worth.

Low down payments but I can still use them as leverage.

1099, social security, trust payments, annuities, etc?

.#1 sell back to the owner with a Quit Claim deed and a 2nd position mortgage for the amount I have into the property plus interest and a down payment.#2 if the owner doesn't want to buy it back, I can begin collecting rent since I control the deed in my name at that point.  

Many Gen Z buyers, however, are still in the process of securing their down payment funds or comparing loan options when they start making offers, putting them at a significant disadvantage.Looking AheadDespite these challenges, Gen Z homeownership demand remains strong.

This would pay us back less than we were owed but still enough to come out whole.We all tried to negotiate a short payoff with the second-position lender, who foolishly demanded payment in full.

Assuming you currently rent right now, and you are buying the single SFR as a primary, the 3-unit should just be designated as investment and you should be able to use the rents to offset the payment (up to basically 'zero-ing' it out, on paper).