"I know the sale triggers both a capital gain on the sale and a reportable Gift Tax amount on Form 709"

Looks to me like it triggers a nondeductible loss from a sale to a related party.  You're right about the gift tax, though, and the nuisance Form 709 return that likely means nothing but paperwork for you and a higher fee for the client.  

"I know that there will be another 6 months of income and expenses including depreciation on the property up until the sale as well but that should be a negligible amount." 

They're still denying that they haven't  been renting it for less than fair value for six years?  Sure.  Right.