I think it's very likely that Camilla will be styled Queen because Charles clearly adores her & will want his wife to have the proper title rather than a lesser one. He knows that names/titles have strong emotional attachments so BP will probably refer to her as Queen Camilla as much as possible rather than The Queen, at least until people become accustomed to her status.
Queen Camilla would be the style of a dowager queen. If they don't feel comfortable calling her The Queen, then I suggest they call her The Princess Consort (as Charles said he intended to do when he got married).