Yes, when you force a full re-import it will import all posts and create missing ones. And update the ones which can be found if you set it to on.
The latest post not being imported is a bit curious. Ill think about that.
The emailing situation is likely due to something set up at your site - an emailer which mails when a new posts are made probably. Thats not at Patreon or Plugin feature so you may be able to do something about that within that particular emailer plugin.