Yes, users need to be approved by staff before they are allowed to login.
This is configurable and can show the entire list to members or just show the number of members on a book. If a local has more specific needs, further customization is available.
Notifications are sent when the monthly re-sign period begins, when they are selected or not selected for a job call, when new job calls for the day are available, and when membership dues are due. These are all configurable by the member.