I feel confidant that your knowledge and expertise will bring you much success in your market.  

Is your DSCR ratio greater than 1-meaning are you cash flowing (according to the lender's criteria of mortgage, property taxes and insurance (and HOA) if applicable).

We walked with about $55k of tax free cash on a $147k house with $55k renovation budget.

This is what the assessed tax value will reset to after you purchase.  

Second, working with a local real estate professional who has experience and expertise in the Phoenix market can be helpful in navigating the current market conditions. 

From there, it's easy enough to look up the tax rate for corporations and make your tax burden assumption.

Additionally, as a co-owner, he would directly benefit from any appreciation, tax deductions, and profits from the property.On the downside, being on the loan could impact his credit score, especially if there are any missed payments or financial issues.

For your sake I would make sure, if you aren't NNN right now, that you at least have RE taxes protection in your lease.   

Buying a primary first will likely give you the best opportunity to qualify for free/cheap money like Down Payment Assistance, grants, and mortgage tax credits.

With rising costs like HOA fees, insurance, and property taxes, it’s tempting to push rents higher—but that strategy often backfires  (and IS backfiring), especially in today’s market.Why Overpricing Hurts More Than It HelpsRents have softened, and supply is increasing.