Superb trade idea. Realistic, fair and if Atlanta and Smith don't come to terms, definitely possible. Add Davis for no 2 nd rounder-still fair.
The only thing that scares me about this would be that Smith has an expiring contract. But I would be ok with BC overpaying for once to keep him. If not, you have a lot of cap space and can maybe go after a guy like Millsap or Al Jefferson. Harris' contract is also expiring, so we wouldn't need to be stuck with him.