Even under the rosiest of predictions, we're not going to be able to sign two max-salary guys, not with both Pierce and Rondo on the books. So, a scenario where we get Howard *and* Granger is probably out of the question.
That said, in an ideal world there would be room for one of them. If the Celts could somehow trade for CP3 this off-season, I think it makes the prospect of a D12 / CP3 pair up fairly realistic. Under those circumstances, I could see KG and Ray coming back in reduced roles. Of course, in all likelihood Orlando trades Howard before he becomes a free agent, but one can dream.