If user's 1 free listing is rejected or deleted, they are not able to submit another

Ok, found a workable solution here: How to Manually Adjust Package Limit?

If the listing is rejected, the workaround is to go into the database, wp_comments, find the user ID and set the comment_karma value back to 1.

Seems like that shouldn’t be too difficult to just integrate into the admin so it’s not such a hassle.