Sorry, but there is no way to manage subscriptions with Connections so it sounds like it will not be a good for for your needs. Other users use member plugin to manage subscriptions, but that would still require manual management of the entry with Connections for delisting cancellations. If you decide to go this route; you would need Link to allow the user to submit and maintain their own entry. As for flagging updated entries; there is nothing built in to do this.
I hope that thoroughly answers you’re questions.