You can pour an additional $100k into the property's principle in year 1 but that equity won't do you any good unless you refi, sell, or take out a HELOC (i.e. your monthly payments will be unchanged)... make your money work while you do, invest elsewhere 

I think it's an amazing program and a great way to literally build equity with very little initial investment.

A 10 year amortization really helps build equity quickly, but you'll be pouring an extra thousand a month into the property during that time (rough guess, figure out all your expenses). 

Mortgage is $374 and rents are $1350, so we took that equity and bought our second duplex.

They're willing to sign it over to me, but wish to remain partial partners since they're doing me a favor.

The house needed some sweat equity in the basement to finish off. 

He didn't have any equity to pay an agent and he couldn't pay them out of his own pocket.

And in every locality that makes up tenant-favorable protective policies like the ones you've laid out, OC always, always benefits.

The cash flow isn’t great as a rental and it has major equity built up.

I have a rental condo in Little Italy in San Diego that breaks even monthly with $200k equity in it.