I am not interested in investing with anyone, just looking for some advice on how to scale without giving up too much cash flow.

In a similar but smaller scale situation I had my real estate attorney reach out to the law firm listed as the LLC's representative (this was for a single unit not whole buildings) and it turned out the owner was letting their kid live there and didn't have interest in selling for that reason but I felt it was worth the tryI hope to hear more updates from you @Cole Barthel !!

I’m hoping to scale beyond 50 units and want to be able to make the right decision for my own property based on market conditions.

My goal with RE investing is to build enough passive incoe to one day soon leave my 9-5 and, along with my partner Account Closed, be able to dedicate myself full time to scaling our business. 

I would also recommend all three of David's BiggerPockets books for agents, Sold, Skill, Scale.

It really makes sense to me to hold onto the duplex or condos if you decided to split them for the long term and keep your focus on scaling with your HELOC and $15k saved, but again I am not sure what returns you are seeing if you do a 1031.

Personally I dislike HOA's, scale deliberately and dont overleverage.

That presents a great opportunity, however it is hard to scale when buying everything with cash. 

I want to scale, but all of these loans make it very difficult.

I have an opportunity to construct a mixed-use building with 42 residential units (each around 600 sq. ft. with 1+ bedrooms) and 2 commercial spaces, totaling approximately 42,000 sq. ft.We have a solid understanding of constructing smaller projects, such as 2-4 unit buildings, but this larger scale is new to us.