Pretty sure they're speakers that light up, though I suppose if you're not interested in playing music from them you could use big flashlight bulbs...they do look similar.
I'm not sure -what- her tail is doing there. I imagine it coming out of the button thing and going "pop!" XD; For my Yuzuki cosplay I was just going to have a bunny tail there always.
Currently cosplaying at Dallas and San Antonio, TX Conventions as:
Shameimaru Aya (usually Fri/Sat)
Karisawa Erika (usually Sundays)
Ryuugajou Nanana, Seychelles (rarely)