What happens if an Endpoint Agent is deployed and policies are downloaded, it is then removed from the network and the server’s license key expires while the Endpoint Agent is disconnected.  Will it continue to work with the latest policies it had or is the license expiration information downloaded to the agent to instruct it to stop working on the same date as the server’s?

The License Key on the Endpoint is the same as the License Key on the Server.  When the License Key expires on the Server, it will also expire on the Endpoint, even if the Endpoint is not connected to the network.

Once the license key has expired, the Endpoint Agent will still send incidents that were created before the license expired.  New incidents will not be detected once the license expires.