Page 253. " the little drummer boy had no gifts to bring "

Little Drummer Boy (performed here by Rolf Harris) was written by pianist Katherine K Davis.

Page 261. " 'Who's Mike Ainsel?' "

Shadows's new identity, Mike Ainsel is obviously a reference to the fairy tale name 'My Ainsel,' (My Own Self.)

Page 261. " the unlikely name of Emerson Borson "

As shown with the name Mike Ainsel (My own self) Emerson translates to Ymir's son, Ymir founded the frost giants and in some versions of the myths is Odin's great grandfather and Borson translates to Borr's son, Borr is the father of Odin, so although Wednesday calls it an unlikely name, it actually fits him perfectly.

Page 270. " My name's Hinzelmann. "

 

Hinzelmann is the name of a kobold, (a German sprite,) sometimes known also as 'Luring'. Like most sprites, Hinzelmann could be benevolent or malicious.  He often took the form of a child wearing red velvet but his true form was that of a very young child who had been stabbed with two swords. Legend has it that he haunted the castle Hudemuhlen.

Page 274. " It felt as hard and calloused as an oak branch. "

Old Oak Tree
Creative Commons Attribution Share AlikeOld Oak Tree - Credit: AnemoneProjectors (talk)
When Shadow shakes Hinzelmann's hand, he is reminded of an oak tree. The oak is a symbol of strength and is the national tree of several countries including Germany, where Hinzelmann is from.