In addition we buy pure rentals on the side.

I'm purely guessing, but there could be an uptick in TV and film people flocking to Atlanta because of the all the work it provides, and who might be looking for short term rental units to stay in.A lot of my production work deals in neighborhoods with high crime rates, so at least I'm learning where NOT to purchase!

As we have built are careers up we save one income and invest the other into pure rentals.

The prior standard required parking - now additional parking is only required if you go to 2 bedrooms.The downside is that they left the requirement in that the owner must reside on-site (in the main house), so it limits usability as a pure investment/flip approach.As @Teri S. says, it may be better to try and convert to a true duplex. 

At this point I plan to start using outside investment.I've also been toying with the idea of investing outside Austin, as investors in this area are forgoing all cash flows and banking on pure appreciation.

My first purely investment deal was a two-family house in a suburb about 20 minutes from where I live. 

Over time that will eat into your profitability quite a bit.2) Purely a guess -- but if you buy in the right areas I would say appreciation will be better long term here as well.

Is this purely due to the loan type?

From fix and flip to pure rentals to section 8 to BRRR.  

Question here is can an LLC get financing or will it have to buy in pure cash?