None of these really are a "discussion" (IMHO "previous discussion" links have two purposes: either to show something has recently had active discussion and therefore shouldn't be reposted, or to link to very old discussions that might be of interest. For me, linking empty discussions doesn't add anything useful)
Same user is fine and might actually mean that the mods asked the user to repost (although dang probably would have mentioned it if they did in this case)