Given that Bush needs congresses approval for who ever he picks, he might side step the whole issue. He throws up nomonies he would like to have in place, but knows likely will not be approved. That is the smoke screen. the real trick is for Gonzalez to promote someone Bush likes to second in charge, then when Gonzalez steps down Bush keeps congress busy with bogus nominations and gets what he wants from his inside man now the acting head of the Attorney Generals Office.
Congress won't like what the temporary head does, but if they complain, Bush will tell them that this wouldn't be an issue if they would just approve one of his nominations, pushing the blame onto Democrats in congress and making himself possibly looks good.
That's my guess as to how this will play out.