You talking about Elmo's Super Numbers, slated to be released on October 7,
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's birthday?
Edit: And if that is
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's costume, then shouldn't we call him Fourschach.
So far...
Super Mario Brothers, AM with "2" on his overalls as Luigi? and Muppet squirrel with "3" on red cap, tribute to Tanooki Mario?
Dr. Two (Mando) with "NUMERATE!" Dallek.
Princess Threea (Leela).
Fourschach, from The Watchmen (Cookie Monster).
Fiverine.
Toughpigs' Joe Hennes as #6, identity unknown.
Nick Furry (Grover) & The Sevengers.
Green Lan-Ten (Muppet unknown).