I think it is just possible - just - that the reason Bannon has made no appearances thus far is that perhaps - perhaps - the RNC is telling Trump that he's f-ing insane and they will withdraw the funding if Bannon is running Trump's campaign.
Because Bannon will decimate just about everything - just about - including the Republican majorities in the Senate and the House in the attempt to elevate Trump and the conspiratorial right over Clinton. This means lying, scandal-mongering and everything else.
Even the Republican Party believes itself to be honourable. And Bannon looks like a step or ten too far.