Real estate professional and QBI deduction are loosely - at best related.

The only reason you would be asking about a real estate professional is because their rental activities are at a loss and they would not otherwise be deductible.

So you want LTCG treatment for the "investment properties" while deducting ordinary losses of for the rental activities due to "real estate professional status" 

Sure, why not.  You probably wont get audited anyway.  Then if you were audited I'm sure you could explain how your real estate professional's investment in the other properties were not in fact a part of his professional real estate activities, but rather completely separate investment activities.

Mind if I ask who your E&O carries is?