Music/Song in Eclogue 4

People/Divinities
Apollo (4.10, 67); Calliopea (4.67); Sicelides Musae (4.1); concordes...Parcae (4.47); Cumaei, i.e. the Sibyl (4.4); Pan (4.58-9)
All, of course, hold their own significance for music and song.  Apollo would seem to be at the top of the pack.  Calliope is the muse of epic poetry, but her role as mother of Orpheus and Linus seems to play the more important role here.
Interestingly, Sicelides, Parcae, and Cumaei all firmly situate these divinities (if you want to consider the Sibyl a deity), in the Roman tradition.

Sibylline Prophecies
Apparently given a healthy description in the Aeneid.
  
Similarities and Differences with Virgil's poetry (needs elaboration):
Divinely inspired
Distinct purposes

Thracius Orpheus (4.55); Orphei (4.57); Linus (4.56); Lino (4.57)
Half-brothers, Calliope is their mother and Apollo is Linus's father.  Linus was also Orpheus's teacher.  The quintessential poets/singer/songwriters.  Linus is also a character (Hercules' teacher) in Theocritus's 24th Idyll, in which Theocritus, through Tiresias, prophesies Hercules' life to Alcmena.  I wasn't able to take a look at this Idyll, but it sounds similar to the prophetic tone of Eclogue 4.

Pollio (4.12)
We have the statesmen again, whose consulship will seem to usher in the dawn of a new age.  Also, reportedly (Eclogue 3), a poet himself.

Music/Song words:
canamus (4.1); canimus (4.3); Cumaei...carminis (4.4); carminibus (4.55)
paulo maiora canamus in the first line would seem to place this song outside of the typical context for his Eclogues (as Professor Malamud and Ebbeler (2010) have noted).

ridenti (4.20); risu (4.60) risere (4.62)
I have the idea of a sing-song quality to laughter, perhaps associated with the Nymphs or maybe the Muses themselves?

It's a strange juxtaposition of prophetic tone, epic grandeur, and bucolic thematics.  19-30 is probably the most pastoral of this poem, but even this is slightly off-putting because the farmers/ploughmen/herders are rendered useless by nature fulfilling these roles of its/her own accord.  The words themselves are indicative of pastoral life, but the message of the prophetic song is suggestive of ending the pastoral world as contemporary life knows it.
Does it elevate bucolic poetry or destroy it?