Good. One down, and one to go.
Double check to make sure that the Windows Defender
service is enabled, but only set to "Manual" and not started.
You shouldn't be getting a message from Action Center
about Windows Defender since you have MSE installed. You might see if reinstalling the latest version of MSE may stop it. If not, then please a screenshot
of the message for this in Action Cente. It'll be like the orange security one below, but may be a different color (ex: red).