Your DTI for a mortgage is based on the mortgage payment.

The only way out is if you gave notice of a rent increase (6 months notice), and they don't pay it, you would start eviction procedure for non payment(if they don't have kids in school). 

The cash you get form either of those options helps to cover the down payment on future purchases.After you have purchased a few homes and have a good chunk of change you can get into 5+ units and start using DSCR to buy apartment style homes where you can focus on affordable living options and things like section 8.

rehab / rent it out and then save again for down payment on next property. 

Sending an account to collections doesn't guarantee payment or specify when it will be received, but it definitely gets their attention.

I am working with a lender that can liquidate credit cards for 10% to use on a down payment on a Tri-plex.

The underwriting costs for a traditional lender will be $100k so for small portfolios it is not worth it.Have you considered getting a warehouse line from a non-bank lender?

I make $100k a year and only have one vehicle payment for total debt. 

I just had $100M in non performing private lending loans come across my desk.  

It's a good idea to have a non-disclosure agreement (NDA) in place with anyone you share your plans with.