Emma is the name of a background character who resembles Emily in appearance and dress. Her name is revealed in a What's Your Favorite Word? interview she gave when she was 11 (now 12), at which time her favorite word was "Razzle-Dazzle".
She has long black hair tied back in a ponytail and wears a blue shirt under a pink dress.
She is part of Becky's class, and sits beside Eugene a couple rows back. She and Eugene are good friends, and are often seen hanging out together.
Emma has a cat costume that she seems to enjoy dressing up in. See Becky and the Bard and Tobey's Tricks and Treats.
Interview from WYFW=
My favorite word is "Razzle-dazzle." It's loud, it's bright... I just like to say it all day long. Razzle-dazzle, razzle-dazzle. So many z's. Razzle-dazzle. My room is probably razzle-dazzly-ish. RAZZLE-DAZZLE!