The episode states that the Winter solstice is longest night of the year, not that it is the longest day. The Winter solstice is the longest night of the year.
As the scene transitions to Lady Jaye walking through the manor with a candelabra, the painting of Destro's ancestor can briefly be seen to turn it's head to follow her movements.
This episode reveals Lady Jaye's real name; Allison Hart-Burnett
This is the second time Destro wears a cape with his outfit. The first time was in his first appearance in the Mass Device mini series
Despite what is said in the episode, the Winter Solstice is not the longest day of the year. It is the shortest.