The article is off because it is comparing two different types of buyers.  

I've dabbled in learning different areas before, but never been focused.

You can't buy your new primary residence with it.But, here's where you could make it all work.1.

Purchase price: $325,000 Cash invested: $150,000 This was our first primary home and was converted to rental after living in it for 10 years.

The Fannie and Freddie programs handle this issue slightly differently.

From tax stand point I would think you can separate from primary and be okay with IRS being that IRS will not be local code enforcement.  

This was our first primary residence How did you find this deal and how did you negotiate it?

I’ve read in books of people getting past having to live in the property they own so they can rent all units year one of ownership(living on the property with an rv). Are there other more creative ways to start cash f...

Now, lets talk about BRRRR and a primary.

Quote from @Brandon Croucier: That’s a killer loan if they are actually offering that.Seems extremely below market value as even primary mortgages are higher than this right now.I would beware of a bait & switch on this.