If you have a HELOC you can pay it back to the "mortgage" thereby lowering your principal and reducing the interest charged.

We are well past the "Break Even" occupancy rate, covering all costs and Principal/Interest, thus this is not a low "Cash Flow" issue, but a Rent Up approach. 10x20- about 1/3 full. 

I would calculate to see what your PITI (principal, interest, taxes, insurance) would be monthly. 2) House hack!

But on top of just simple ROI and ROE, you need to calculate your net worth returns from writing off interest expense, principal paydown on two properties, appreciation on two properties, etc.

@David PalmerDepending on your experience and the experience of the GP; 5%-10% of the GP for a Key Principal. 

Not much benefit the money down would decrease the principal balance which would then lower your monthly payment.

@Andrew JacksonThe tax implications will depend on how the funds are given to you.Are the funds given to you as 'debt' where there is a promise to pay back the principal along with interest?

Nonqualified Use.The gain exclusion from the sale of a principal residence ($500,000 for joint filers and $250,000 for single filers) is not available to taxpayers for periods of nonqualified use.

You won't build up much equity through paying your mortgage in 2 years due to how the principal and interest payments work-go to a website for a big bank in Canada and look at the principal vs interest chart for a mortgage-most of the payments go to interest at the start.

Just principal reduction alone will generate an 8%-9% return on your money the first few years.