Yes indeed, phpList has quite a strong unsubscribe function as part of it’s “permission marketing” method. It’s quite key to how the software works (though we often discuss how to soften it a little)
Yes, or more simply just use a template which points people firmly at [PREFRENCESURL] and a really clear subscribe / unsubscribe page to people can opt in or out of lists as they please. Then your unsubscribeurl as a less obvious option in the footer etc. That way those who really want to get out can do, but those who just want to tweak their membership have the best chance 
The happier your lists the better