thank you for your post.
1. No, there is no limit, every user can post several posts. We can try to add a setting to limit each user to post only one single post (or 2, 3, or 4…). If we find a way, we’ll include it in the next update
2. Normally there is a list in the front-end with all published posts, + buttons to edit the post. You can use this shortcode to display that list:
3. Add the moment there is no way to change the default fields for the posts, but we are working already on a customizable frontend submission form, but it will take at least 3-4 weeks before we can publish the update with this feature.