Just as a very simple example:
Run a: "netstat -c -t" before opening firefox, and after all previously open connections are closed.
Then open firefox and see what happens.
My guess is, from this very angle there was a single good source, and all media copied/bought it.
In the 1080p version of the CNBC stream at 29:16 one can see the firefighters appear.
www.youtube.com/watch?v=XljT1he8Jjo&t=1756
In a zoom a bit later starting 42:55:
www.youtube.com/watch?v=XljT1he8Jjo&t=2575
one can see them work very clearly on a large screen.