Gave up on the snippets. I resolved the WPUF IE8 compatibility issues, and eventually settled on it. A combination of Gravity Forms and WPUF allows my users to register, and create a posts. When viewing their posts, they can upload attachments as proper post-attachments without visiting the backend. All users can see each other's posts and attachments, but only the post author can upload attachments to a post.
Now we have a proper frontend user-based content and file upload system!
For those looking to achieve a similar setup....
My overall post creation and user attachment management system work like this. Users register and create their post via Gravity Forms. The GF Form appends the [wpuf-edit] shortcode into the post body. I made a some slight edits to wpuf-edit-post.php to HIDE the Title and Body form edit fields and leave only the add attachment.
When browsing posts, the user can't edit the title or body, but they CAN add attachments or participate in comments. No need to visit the backend, and all media resides in the media gallery proper as post attachments.