Ben calls the shots on who will replace Haley if he goes - with that talent the Steelers would have no trouble attracting outside candidates but I assume Randy Fitchner would get it
As for Butler and the defensive coaches the failure to develop first round picks Jones & Dupree does not reflect well on Porter (or those who made the picks) and the ongoing secondary problems should put Lake in jeopardy. Butler's defenses have been shredded in the playoffs the past two seasons by Brady (who has done it to everyone) and by Jax (which is inexcusable).
If Cowher was the HC heads would roll - he regularly whacked assistants. If changes are made now it will be because AJRII demands it, as he did with Arains after the 2011 season. My guess is Haley goes along with one or more defensive assistants below Butler.
If changes are made it should happen quickly rather than wait for the new HCs to assemble their staffs.