Is that a trick question?

It's irrelevant what I think, because both of them aren't joining, and are well beyond our price range.
However, just to humor you,and respond to your question, the answer is a resounding yes, particularly Higuain. Benzema might score the same number of goals, or perhaps a few less, but his all round game is much superior to Dzeko's. Higuain and Benz are vastly superior to Dzeko, and both would definitely elevate us to another level (especially Benz with his all round play; I rate him as highly as Aguero or Rooney), but sadly it shall remain a pipe dream