Thanks Evan, these are the type of answers I couldn`t seem to get specifically unless it was through non accredited investors that been around the block in those circles (outside of Rise 48 and Spark Rental).

Or can you line it with concrete, and make it 30 feet deeper, with a smaller footprint, or put in several smaller ones?

Slab over Basement, Wood or Block,  Many factors come into play.  

You're going to have to do a lot of blocking and tackling to find good vendors.

Then I would give that number to the tenant and block their number on my phone's main number.

What I can assume is most AZ HOA's don't allow building new structures above the height of the exterior block walls.

43608 (and the similar single-digit zip codes) fall into the 80/20 rule...stay out of 80% of them and the quality changes with every block.

The neighborhood was also too dense and the block was over capacity for multi family rental units.   

There are a lot of opinions about which is better but nothing concrete.

I had a consultation with them last summer and feel like I need more professional help but just can't pull the trigger for the promise of what could be without concrete guarantees it will be worth it...