The Ashes: Questions for England after Australia defeat - should Brendon McCullum and Ben Stokes stay on and who comes into Test team?

What next for England after their 4-1 Ashes series defeat in Australia? Could Sir Alastair Cook come in as an assistant coach? Who should England build the team around over the next four years? What next for Zak Crawley and Shoaib Bashir and who else could come into the fold?