One of these agencies is not going to comply. And then what? Trump is already pushing the legal “theory” that the judiciary cannot check the executive. This is bound to end up in front of the Supreme Court, and who knows what those guys will do?
I think we all know, it's been choreographed for decades now. The supreme court exists as a means of rubber-stamping republican legislation.
That said, in reality, I don't expect there will be any real pushback. It'll be people attempting to work in the constrains of a new system and life will largely still be mostly normal for folks.