You can do all of this in Filemaker if you host a solution so that everyone has access to it.
You need to work out a basic data model with tables and relationships before you worry about "tricks".
Notifications can be sent out via email or as messages that pop up in FileMaker at the time that a user logs in. I've set that kind of system both ways. The advantage to "inside FileMaker" notifications is that it's very easy to provide a button to click that takes the user to the correct layout and document to view the information about which they are receiving a notification. The disadvantage is that they have to open FileMaker before they see the notification.