You don't need to upgrade firmware on your ESCs, you just need to do the throttle calibration, so they know what signals to expect.
Beeps are more or less the only way in which ESCs communicate with the user, GCS only shows what signal it's sending to the ESCs and nothing more.
This depends on the kind of ESCs being used, but all the ESCs I've come across do some short "hey I'm alive" beeps when they get connected to the battery.
Possible following beeps can signify that zero throttle signal hasn't been received or that programming mode has been enterd (again refer to the ESC manual for details).
I haven't had an ESC that beeps during it's firmware upgrade procedure, so that's normal.
The noisy beep you described might signify faulty ESCs.
Some ESCs can produce a decently loud beep, but as you described it: "...such a loud noise nothing else can be heard." is a bit hard to believe (try using an angel grinder for half an hour, that's loud
).
Healthy ESCs make nice consistent beeps and not some random rubbish.
You don't need to have the radio set up complete to get the motors set up.
For a basic setup, if you follow trough the vehicle setup wizard and your hardware is in working order you should be good.
I know of a site, it's called YouTube
here's a link for a playlist that might be very helpful:
https://www.youtube.com/playlist?list=PLYsWjANuAm4r-E61stLchCR4bzY3NmDNhAlso there's LibrePilot Wiki:
https://librepilot.atlassian.net/wiki/display/LPDOC/User+Manual