In ALM do all users in the development model have to be pushed to the production model? For instance if we are making 3 different copies of the DEV model will the users need to be the same accross all 3 production models? Any other useful information of users moving from DEV to PRD would be extremely useful.
Users are not pushed during a sync, this way, you can keep your developers and production users separate. The only user needed in both models is the person doing the sync and they have to be a workspace admin (WSA).
Everything related to user access like adding and deleting users, role assignment to users, selective access, etc are done at model level irrespective of whether it is dev or deployed model. Whereas, other role based access controls are controlled in dev model.