When I delete a list, are the leads on that list also deleted?

When a list is deleted, leads who are associated with that list will remain in the system. Lists are

virtual buckets used to segment certain leads from the rest of your lead pool.

For example, when you import a lead list in PUBLITRAC, a new list will be created for you and all imported leads will be associated with this new list. If you ever delete that list the leads will still exist in PUBLITRAC.