Those haven't been problems for the teams I've been on, and we've always been "every man for himself" when it comes to dev environment. As long as code follows the style guide, passes tests and gets through a code review, nobody cares about the dev's environment. Did you try that and it didn't work? What led to management mandating conformity?
I have never before or since worked at a company that allowed "every man for himself" while managing to enforce the discipline required to maintain a uniform style guide, tests always passing and code review. It was nice to go over to a colleague's computer and see exactly the same code as I see on my own, and in the same environment. Everyone used the same debugger interface and same unit test interface, because everyone used the same IDE. They become more natural to use. People were able to refactor easily and maintain consistent naming standards, which is more difficult in Emacs, and especially in vim.