Chris's song Mayumi Ichii-Bal has her repeatedly singing "zenbu", so fans have often taken to referring to her as Zenbu.
Since she has blonde hair and her Symphogear outfit resembles that of a witch, Kirika is known by some fans as Dark Magician Girl (or DMG for short).
Both Shirabe's relatively serious nature and Weapon of Choice have earned her the nickname Buzzkill.
God Never Said That: Contrary to popular belief, the show was not a 2 cour (26 episodes) run that was switched to 1 cour (13 episodes) midway. Symphogear was always intended to be one cour, it's just that there were too many ideas and they had to be cut out. You can read more about it here.
Name's the Same: Hibiki and Kanade are also the names of the first two heroines of Suite Precure, another music themed magical girl anime. The evil force Noise is also the name of Suite Precure's Big Bad. Second season adds up a new antagonist whose first name is Shirabe, which is also the last name of Suite Precure's final Fourth Cure. Another new antagonist, Maria Cadenzavna Eve shares the same first name with Suite Precure's Hibiki's mother.