✅ Purchase Price of $28K per Door✅ Property Condition Newer Roofs, Well maintained, No Major Foundation or Plumbing Issues✅ Property Characteristics Individual HVAC & Water Heaters, Great Unit Mix, Large Floorplans, Great Amenities Including Pools, Gym, Sauna & Playgrounds ✅ Cash Flowing from day one✅ Conservative Underwriting✅ Cost SegregationHow did you find this deal and how did you negotiate it?

If you've already got a good gravel base without the need for any real earth work and just need to pay for slab, building and basic electrical you could come in as low as $20 per square foot but as you mention is will depend on your building size and unit mix. 

My long-term vision with attending these meetings is to bring up new ideas like including more mixed-use zoning, building better pedestrian and bicycle infrastructure. 

It has parking for 60 vehicles, a diesel generator, a mix of small and large offices, a large meeting room, and a large kitchen.

Up to this point, the rents paid by tenants on these properties have gone into segregated accounts (not mixed with my own money).

I have also heard mixed review about an llc vs insurance.

With buy and hold, though it can be passive in nature, allows for so many levers to be pulled by the more active investor to force this appreciation and unlock even more earning potential.If your main goal is for that purely passive, diversified play, REITs provide a great option, but if you are looking to maximize the return on your invested dollars, though possibly more risky, getting into the mix as a buy and hold investor provides for the opportunity to accomplish so much more.  

And I would get the tenants car liability insurance in to the mix asap. 

Is it better to have all residential, a mix, or all commercial?

If that property is a mixed you have to get a commercial insurance in order to close and they are a little difficult to get on your own.Hopefully that helps with a step down the line a bit, if you need any assistance please feel free to real out.