Luke Mably is the only actor to reprise his role from The Prince and Me (2004). However he was replaced by Chris Geere in The Prince & Me 3: A Royal Honeymoon (2008).
Jonathan Firth who plays Soren in this sequel is the brother of Colin Firth, who played a British King in The King's Speech (2010).
No King of Denmark in real life was ever named Edvard.
During the intro the castle shown is Frederiksborg Castle in Hillerød, north of Copenhagen. First you see it from the outside - later inside the courtyard. The city otherwise shown is not Copenhagen