Can I get a conventional mortgage with 10% down on a 3-unit building where one of the units is a commercial space accounting for half of the square footage?

While I have a few in mind, I would love to work with a broker or agent that is actively involved in REI. 

I've been involved in several lawsuits, both as an officer and a resident and I've NEVER been on the losing side in any of them.By-laws are just that, LAWS, as I told the guy who replaced me on my local board here.

I'm not familiar with using the term "professional landlord" in the context of driving tax strategy (just "real estate professional" vs "not a real estate professional", which is determined by hours involved, not scale).

(i.e. there's still some risk, stress, etc. involved) Not to mention that paying 10% + leasing fees "goes up my bum sideways!

This unit in Butler Tarkington area of Indianapolis seems to fit the bill (though that square footage seems unbelievably high... are they including the unfinished basement in the calculation?)

If the purchase price is less than the debt then you have a short sale situation which would involve asking the lender to postpone the sale so you can go through the short sale process. 

Once the tenancy ends the tenant should not be involved in the place in any way.

Make sure you check to see if they're involved in and organization like NARPM (National Association of Residential Property Management). 

If you are seeking legal advice involving the tenant, you can let your attorney see the document.