OccupancyMost lenders require a minimum occupancy rate of 85%.

Another note on construction cost, going vertical is very expensive now and would require have a great connect with a developer and a builder in the area.See what rents are in the area and run the numbers to ensure the rents will cover your costs and give you a solid return—using the 1% rule can help.

The down fall is a Heloc can "Never" be used as an asset or for PITI reserves required when buying a new Primary or investment property.A heloc can also cause major issues with credit and one slight hiccup or missed payment the bank or lender who is holding the Heloc can close or reduce your line of credit.

Be sure to do your due diligence and make sure the PMC is licensed (if required, it's not in all states) and insured.

Make sure any lease agreement you use complies with Arizona's landlord-tenant laws, including required disclosures (like bed bug information, for example).If you're unsure, consulting with a local real estate attorney to review the agreement can provide peace of mind and ensure you're fully protected.

You should not get a PM until you have scaled to a level that requires it.

or if not 50% capital required why wouldn't the other partner just find a realtor and CPA to find/underwrite the deal and 3-5% for property management then own/keep 100%?

As Jonathan mentioned it can be done, but they may require an appraisal of the property. 

The lender will require that you live in it for 12 months and then you can rent out all of the units after that and start the buying process using the same strategy all over again after that 12 month period.  

The interest rate is nice, if there was a way to increase the cash flow to ~15% or greater COC you could pull a HELOC on the property for 9% and collect the delta.again though, i would suggest selling it and trying to lock up a property or two with the proceeds that required some sweat equity, force appreciation through a reno, rent it out, refinance and repeat (BRRRR)