Integrates with default WP editor and enables you to edit raw post content without filtering.
Easily. You can use all default buttons like
Publish Raw and
Raw Content tab is selected/open it will save that content.
No. On that side this plugin is independent. It will pull content from database as is and it won't sync it to other editors.
It should work unless they are also changing something on default WP content editor.
My preference is using Chrome or Firefox and I would be happy to hear that it is working with other browsers too.