I canīt speak for every player but we try to have as accurate rosters as possible for the playable leagues. Your two examples are in the game and in the Devils franchise. If we have player missing, we will fix rosters of course.
Like in FM your GM/Coach has skills (he always had) and like in FM, in career mode you start with lower skills and raise them when gaining experience. The skills will help you e.g. with coaching, team management, negotiating, etc. In Sandbox mode you still have this skills in the background but they are raised on itīs own over time so the user does not have to bother about stuff like this.
You have both options. We donīt want people to play a team they donīt want to coach, so just pick e.g. your favorite team and start or choose from a few random offers in the beginning.
Since most people here know FM, I can use it as comparison:
Path to Glory (a.k.a. career mode) is basically just like you would play FM (disclaimer: of course FHM is not nearly as deep as FM at this moment but the goal is to slowly evolve the mode into that direction with every update and new version). You canīt edit stuff, you canīt speed sim and you canīt let the AI handle everything. You still can ask your Assistant Manager to do the dressing or build lines if you wish but e.g. roster moves are always your responsibility. And limited is only for your GM/Coach, you can always continue with a new Coach/GM, it just looks strange when you compare with other (historical)
greats and you have hundreds of GP more because you still are on the bench with age 120. 