You'll likely have to cover common area electricity and all of the water (typical for Chicago may be not your case).  2. 

You should know rents, common expenses, vacancy/occupancy rates, etc.   

All owners must hold title as tenants in common under local law.2.

Double closings seem pretty common here.

Specific to commercial real estate in the general sense (non-apartments), your income stream is commonly fixed for a long time, i.e.

Probably the biggest changes will be if the states have different legal structure for spouses, such as tenant in common, etc., and how those are handled when selling a property, as well as the agent responsibility if it is a non-disclosure state vs not.

Our names are all listed on the deed as individuals, tenants-in-common.

The common ground that needs to be present is you need to 100% trust in your partners honesty, integrity, and work ethic.

Is it common knowledge as best business practice or actual business law?  

A common misconception is that one needs to recoup 100% of their cash invested in order to BRRRR - that isn't true.