The clue board that Hook looks at in the beginning has a post-it reading: "the landlord is Yen Sid." Yen Sid is Disney backwards. This is also the name of the Sorcerer in Fantasia (1940).
"Mea culpa, mea culpa, mea maxima culpa" has for centuries been part of the confession of sin in the Roman Rite of the Catholic Church. Originally adapted to secular slang as a true confession of wrongdoing, today it is more often used insincerely as a sarcastic (some would say ironic) denial of any real guilt.
The title is the final track of Bruce Springsteen's 1978 album of the same name. This is the second time a Springsteen song has been used as an episode title for the mid-season premiere, New York City Serenade (2014) being the first.