Answer:  Members will not be specially notified when you create a new policy in the system. However, when they open Members App they see a prompt saying that new policies available to read as shown in the screenshot below. Members will not be able to access any feature in the Members app until they accept and sign the new policy. 

The popup window keeps prompting when members try to use any feature in the App until they read and sign. 

What will those members that are logged out see?
Answer: Members who are logged out can not see anything until they login into the app. 

What will the members see on the portal (including those already logged in)?

Answer :
Members who use web portal will be sent into policies page when they login. The system will not let Members to access until they accept all policies. No options will work in web-portal until member accept all policies. 
This is how it is shown in policies page. 

If members have not signed and accepted them, what will we see on the staff portal and are they able to be placed into shifts?

Answer: System will not let Members to Accept policies without Signature, If they try to do so it prompts as shown in the screenshot below.