For those who need the answer.
Add action item to this folder "/sitecore/client/Applications/ECM/Component/Actions/General/Column/General" for "Sent email campaigns" page a another action item to this folder "/sitecore/client/Applications/ECM/Component/Actions/Message/Column/Message" for email campign detail page
Edit these ...
You can't. There is no difference between someone who has never subscribed and and one who has unsubscribed.
You will need to add your own logic to the HandleListUnsubscribe or UnsubscribeFromList and possibly the UnsubscribeFromAllEvent pipelines.