I deleted UserX account but I still can see UserX posts in the forums. I expected the system to remove those posts but that's not the case. Those post now show with UserX name as a 'guest'. How do I find and remove all of these posts?
My recommendation here would be to never actually delete accounts.
Instead, depersonalise them (change username, remove data) as necessary, and ban them.
It then leaves them in place as a key to find and/or manage content. And as a point of reference in case the deleted account re-appears