Thank you for this explanation. But the feature you're desribing is a feature of a text editor, and not a website builder. Why would need something like that on your website?

Sorry, but I still do not understand what exactly do you need us to do.

No, this is not possible at the moment. Please add another feature request for that.

Could you please describe, what kind of integrations do you need? Maybe a use case scenario would be great.

This option is available is website settings panel. Please contact our online chat support for help on how to do it.

Could you please provide a use case example for this feature?

I'm pretty sure all this is available right now. You can add CMS user, who will be able to manage mailboxes. And all the other features you've mentioned are available as well. Please contact our online chat support for help how to manage email.

This feature is available. You will find "My images and files" button in settings top menu.

Could you please provide a use case for this feature, or an example of what you have in mind?

This is a great idea. Let's vote.