I broker my HELOCs to TCF bank specifically because they will accept Fannie and Freddie's standard methods of calculating DTI (which your local credit union obviously is not) instead of re-inventing the wheel, with the only deviation being that they will calculate their own debt obligation more conservatively (which makes sense given that it's an interest only product in 2nd lien position). 

I would like to do this method, but have 3 little kids and moving that often sounds horrible, even though it dies make me clean out all the stuff I don't need!

Then I will use the BRRRR method (Buy, Rehab, Refinance, Rent out, Repeat) to continue building my portfolio.

There are other methods available for low or no down, but a bank isn't one of them. :)  

Did anybody finance their first property utilizing that method?

It would be helpful to discuss your level of experience and build on that.If you know nothing about real estate, starting with the more risky or complicated methods of acquisition will be frustrating for you, at best.If starting, consider getting your TX agents license if for no other reason that to get a foundation of knowledge.

Buy and hold if that's what the OP wants to do which is the slow drip method unless you have a lot of capital... what's the difference if your making 250 a month positive or 150... its a whopping 1000 bucks a year.. how is that going to change your life. 

You demonstrated that business owners need to be willing to adapt to see success, which is something I truly believe in.

I hear some of the guru's speak about algorithms and various methods as a way of determining the best areas to market in ('best' meaning dollar wise), and that kind of stuff fascinates me, and I would love to know if there is a way for me to find this stuff out?

What's the preferred method to present wholesale deals to several cash rehabbers at the same time?