Questions about using Disqus or Jetpack for comments [closed]

I am using Disqus and can anwser for this platform :

1) You have the option to save comments both on Disqus and locally on WordPress.

2) This way, if you want to switch to default comments, they will already be there. On the other side, you cal also import local comments to Disqus, if you were using the default comment system and want to switch to Disqus.

3,4) You can share your comment once created, you can test this yourself on any disqus enabled website