The barest version of the facts is available here. This provides all of the numbers broken down. It is the story that NV Dems put out on Medium.
64 were questioned by Clinton Campaign. 6 of those were seated. 8 were turned away — these were based on questions of registration, residency, etc. It’s all in the above linked story. The rest of those 64 did not show.
If you were Periscoping inside the convention, those were Credentialed Delegates or, I suppose, someone who was given an Observer Credential. I do not know how Observer or Reporter Credentials were handled so I cannot speak to that but only people with Credentials were allowed inside the Convention.