New Outlook for iOS and Android App Configuration Policy Experience – General App Configuration

Sorry, I have three further questions so I can be 100% sure on expected behaviour before I apply settings to thousands of devices.

1. What happens if you have a published client app (doesn't have to be Outlook).  Users install it, but then later I delete the client app from Intune console (or unassign it from the users).  Does the app get removed from their device or does it remain?

2. What happens when you publish the Outlook app WITH an app configuration policy. Users install it, but Microsoft later release new configuration features which we then configure in the policy to company standards (e.g. 'Organize by thread' defaulting to off) . Would it change the setting for existing installations?

3. What happens when you publish Outlook WITHOUT an app configuration policy. Users install it.  Focused Inbox is therefore on by default.  You then apply a configuration policy with Focused Inbox defaulting to off.  Would it change the setting for existing installations?

Thanks in advance.