investment go bad.So, I'm going to recommend learning how to do multi-family - especially commercial (and what the distinction is) - before jumping in with both feet.Time taken now can prevent big losses down the road.My $0.02...

I have too much to lose to not get this right & it’s critical that my interests are protected.

It's critical to avoid a situation where you have just purchased a second property, put significant money down, and now have to pay for a new furnace ($10k in my area) at the first property. 

@Felipe Ocampo The critical step in the 1031 process is to contract with a Qualified Intermediary (QI), like @Bill Exeter or @Dave Foster before you close on your sale. 

Location for these types of properties is critical.

This distinction makes a huge difference in how an investment may be interpreted.Secondly, why is IRR not included in the BP Calculators or is it and I am somehow missing it?

Each of these jurisdictions has their separate and distinct building departments and jealously guard their distinct prerogatives over their particular slice of the pie.  

Every one of @Mike M.s criticisms are valid. 

Most people I’ve heard about open a special checking account specifically to track expenses, as record keeping is critical.  

Please feel free to add any additional context or suggestions, and let me know if I've missed any critical questions or considerations.