What kind of plugin would?

1. Subscribe to blog see WordPress Feeds
2. Subscribe to comments https://www.google.com/search?q=wordpress+plugin+subscribe+to+comments
3. Yes would need to be a user (you call it member)
4. Delete the user to ban them.

Ok we didn’t understand each other.

Say a guest is viewing my blog. And there is a “subscribe or RSS” button on the top right. In order for them to subscribe or so they would have to be a member. Understand?

And or, how could I ban someone completely from viewing my blog or posts all in all? So there is no way they can see any posts of it what so ever.

members only looks as though it might have some of that functionality.