When Mumble is still a baby, his "bowtie" does not appear until Boss Skua has him pinned down under his foot. Then shortly after, it disappears again, only to reappear when Mumble falls into the crack in the ice.
Norma Jean and Memphis are named for Marilyn Monroe and Elvis. Elvis is from Memphis, Tennessee and some of Memphis's movements are like his. Norma Jean is Marilyn Monroe's birth name and Norma Jean sings like her.