All of the advice I've seen on here (from Brandon's analysis videos and others) says to set aside 5% for vacancy.

Instead, I was able to put down 5%, or $12,000, allowing me to get into the game considerably faster. 

Its amazing people were getting so much money for homes back then with no skin in the game. 

Great summary of the necessary groundwork needed to get in the game.

I know in the video Bryan says wait a year then refinance.

The plan would be to basically use my HELOC as my new checking account, sending all of my direct deposits and income to this account (as explained in all of the 'pay off your mortgage in 5 years' videos).

I was listening to a youtube video regarding purchasing multi family homes and was introduced to another way that I can boost my qualifications for a loan.

But your home where you raise your children is a different ball game.

If so, and you are in second position, if the buyer defaults on the primary mortgage and the lender forecloses, your second position will be wiped out and you will be left with nothing.The fact that the buyer has no actual skin in this game at all, because you are financing the downpayment, seems risky to me.  

If your long game is to hold, then generally speaking, I feel like a good tenant is worth more than a half to full month's rent.