For the Murloc Costume
939231
The Band Members
Orc Singer- 21665
Tauren Drummer- 21661
Bloodelf Guitarist- 21666
Troll Guitarist- 21662
Undead Guitarist- 21659
To apply these simply select the npc or character (even yourself) and type
.morph
Then the code. I can't remember how to chance back at the moment.
FOr an added bonus if you want to hear the poer of the horde song type
.playall 11803