Just to confirm: I have it now officially, that there was no loss of separation at all. The controller restored the scenario in time to avoid a loss of separation (it was only a loss of separation assurance therefore).
I have further confirmed, that the audio has been manipulated/faked. The sounds of the autopilot disconnect wailer as well as the "Traffic! Traffic!" advisory are not present on any other recordings that became available to me in the meantime, including (but not only) LiveATC.
According to information I have received from Ireland during our research the thread initiator here (as well as on boards.ie) and the video author most likely are the same person (and I have more information about that person, which however would be inappropriate to be mentioned here).