Account Lookup by Username -> You can use Formula mode and reference a list of usernames to make this work for many usernames:
Latest Post from Account -> This fetches the latest 12 posts which is the posts displayed on the page when visiting a user. This is because Seotools currently can't handle scrolling. So, its not possible to filter by date.
Post Lookup -> Weird, can you try and update the Connector via the Manager and also reply with the post URL that doesn't work?