Sharon's image of the duke's mother looks like how South Park draws Canadians
Also, some interesting etymologies:
"Gerbera" is a type of daisy
"Viola" is a type of violet
"Walter" is a german word for "brightness" or "power"
Though, "Phillip" would be the oddball because it's ancient Greek for "Lover of horses," so I don't know if it directly refers to the duke. I don't know if the duke, himself, owns the estate, or if this is teasing that someone else owns the deed and the duke is just being allowed to live there