I forgot to mention that I did not have libflashsupport installed for the previous tests, as you requested. It seems that this isn't a solution.
I also tried the ALSA version of Skype (Case 2 configuration), manually set the sound devices to "pulse" and funnily enough, the Skype control appears in the PulseAudio Volume Control, Skype no longer shows any sound warnings/error, but no actual sound is produced, unfortunately.
Alexander,
I forgot to mention that I did not have libflashsupport installed for the previous tests, as you requested. It seems that this isn't a solution.
I also tried the ALSA version of Skype (Case 2 configuration), manually set the sound devices to "pulse" and funnily enough, the Skype control appears in the PulseAudio Volume Control, Skype no longer shows any sound warnings/error, but no actual sound is produced, unfortunately.