Just need to stat under the occupancy limit.Also keep in mind basement needs to be livable square footage, ie have egress and proper ceiling height. 

While metrics like square footage or price per square foot matter, the number of bedrooms, bathrooms, and overall location are often more critical for attracting tenants.Engaging a property manager early on can save you from costly mistakes and help you invest in properties that perform well in the rental market.

At the submitted square footage you provided, that $2M seems wildly out of whack.

I recently added a half bathroom to existing footage in a unit that is valued over $1k/ft that the comps showed the half bathroom added ~$50k of value.- not sure of your home market but i assume you are choosing ohio for its lower cost.  

I've owned my rental SFH for 1.5 years, and noticed my property tax is significantly higher than my neighbors' properties with similar square footage and conditions.  

For example, this can be adding square footage, adding an extra unit, or adding a pool in a STR market/luxury market.  

One that stands out to me is 1801 E 69th Terrace. 3/2 with similar square footage.

Since one unit is int he basement the square footage put me in line with other small duplexes.

All the rest can be subbed out unless you are doing a full remodel by adding square footage to the house/converting a space (bath/bed etc).

How much sq footage does the lot need to qualify for an ADU?