The answer to that question is yes, the pro admins can see hidden forums, sections, etc. There is no way to hide topics in any sort of private section. You need to either just outright delete the posts or edit them to remove any bad content.
There is no hiding any data from our Team of Pro admins / or tech staff if you are thinking you can hide text or items from our staff you can think again your forum will be banned if our system finds it and it WILL TRUST ME...So don't even think about it..