This is very interesting. Who could they potentially be targeting to replace Ibaka at 4, though? With Durant's impending free agency, this makes no sense unless they have someone set to take his spot in the starting lineup. I can't imagine that Kanter is it.
I would certainly think that trading for Ibaka would help in the Durant pursuit, too. I think Bradley would be the guy they'd desire from us.
I'd do Bradley, Young, and 16 or Bradley and KO for Ibaka. You'd have to try and balance making them better and more attractive to Durant versus making us better and more attractive to Durant. We'd still have room for Horford and Durant in this scenario, in addition to the 3 pick.