Considering that actual North Pole elves we see in Elf have names like "Pom Pom," "Ming Ming," and "Foom Foom," "Crumpet" is pretty normal. It's also probably a nod to David Sedaris' essay "Santaland Diaries," where he spent a holiday season working as "Crumpet," one of Santa's elves at Macy's in New York City.