If there was a rental to Tenant A followed by a sale to Buyer B, I would treat it as a rental and claim depreciation and other expenses against that income.  But when Tenant A and Buyer A are the same person, I would want to know more.  Was the lease and the purchase all part of the same contract?  Was there a reason to let the buyer move in before closing (related parties, perhaps)?  

The sale will probably show a loss because of selling expenses and if shown on Part II of Form 4797, flow straight through to the 1041.  Does that make a difference on the Schedules K-1, especially if it's not a final-year return?  If it makes a difference, does that help or hurt the beneficiaries (not that it should matter if you're just trying to do the right thing).  If it doesn't make a difference, why complicate the return?