As a site admin, how do I find where content marked as "Hidden Content" in a community is so that I can either review and/or delete it? If hidden content posted in a private community, how do I at least see who the admins are of this community, so I can reach out for their assistance with the hidden content?
Reviewing through your description, as a full access admin account, you should have access to all content present in your instance. However, if you are seeing hidden content I would recommend submitting a case in your customer group as a next step. When doing so, please provide the following as it should assist the support member assigned to the case:
1. A screenshot of the behavior
2. The username of your account