In the long run this ridiculous thought process is going to end up biting this country in the rear.

Front, rear or side entry on the garage?  

I’d like to ask you what strategy of RE are you doing in OH? 

SINGLE GIANT CASTING of the rear body-  79 parts put into 1 part.   

The rear addition which faces south in south florida was ridiculously hot.wound up putting in two mini splits.cost mini split x 2 840.00Parts and labor which included 2 30 amp fuses, wire and breaker box 1600 installed.way more efficient than my two condenser/ handler units.I saw the electric bill drop and tenants are happy.look up McCool mini splits on YouTube.I figure if it can keep a house Ice Cold in the Caribbean why not Florida. 

Should I bash two halls in the rear of our six-unit brownstone for through wall A/C or install a mini split system?

And you'd have to assume (for the future fee) that I'm going to go home, practice my rear-end off, etc. 

Back to your post the bankers couldn't find their rear ends with both hands.

Be polite but definitely cover your rear on this - check out the pinned "evicting renter from a vacation property" thread for the worst-case scenario. 

Things to look at would be lot coverage restrictions (anything covered such as carports and patios would be included in square footage) and set backs.It looks like your main obstacle would be the setback on the rear of the property as that workshop is basically on the rear property line.