We have a house in an opportunity zone in Texas that we bought in 2015, lived in for 3 years, and then made a rental in 2018.   

a lot of people will poo poo this, but I also live in a market where cash flow is low, property taxes are high and properties are expensive (which is a relative term).

What zoning code could I request a zoning variance or rezoning that would allow us to have the 2 livable units on parcel, one primary residence and one additional living unit (known currently as ADU)?

If you're willing and able, I do recommend the "house hacking" strategy which is just a fancy name for buying a rental property and living in one of the units, because you'll get very favorable financing - an owner-occupied fixed-rate 30-year mortgage.I'd also say, analyze that property as if you won't live there and it's a pure rental, and make sure the property is still cash flow positive if there's a tenant in your unit because then you'll know if it's actually a good investment.And when you analyze it, include payment of a property manager in your #s because if you don't, and doing so would make it go cash flow negative, then you've just bought yourself a job because you literally can't step away from managing it without losing money.

Hey, I was taught pimps and ho's and gang bangers gotta live somewhere too.

I've lived in Fishers/Carmel my entire life and know the market well. 

You can also contact a local alcoholics anonymous or other organizations and let them know you have space available for anyone living sober.

One potential route is using a FHA 203k loan for the purchase and rehab if you're okay with living in one of the units for a period of time.

Anyone who lives in and around this area clearly understands that Baltimore and Baltimore County are very different than DC.

On the rental agreement it should clearly state that only those listed on the lease are allowed to live in the property.