When creating coach characters for a 32-user offline CFM, you can set up most roster management tasks - fill roster, offseason free agent signing, depth chart reordering - to be performed by the CPU.
The draft is likely going to be something you have to button through (though you can delegate individual picks to the CPU), and trades won't happen in a 32-user setting unless you force them to happen.
What one might do is "retire" the created coach characters right as the offseason starts (after resetting their team scheme settings back to the default values) to give the AI full control of its roster management. Retiring an existing coach character does not remove him from the game; i.e. if my character is Jason Garrett and I retire him, Jason Garrett remains in the game save and remains the head coach of the Cowboys, but I lose control of him and can no longer perform any roster moves as the Cowboys.