Bannon gave Wolff a WH pass and invited him in day after day. Why do you think Priebus was fired? It is likely that he approved.
Not everyone in the WH in the earlier days wanted Trump to succeed. Bannon was spreading the word that if he ran for POTUS, the Mercers would back him. Do the math.
I find the idea of Steve Bannon undermining President Trump in order to run for President himself hard to believe but I appreciate the insight.