For example 2017’s Christmas Inheritance is also on TV in the first Princess Switch and in 2018’s The Holiday Calendar and A Christmas Prince is also on TV in The Holiday Calendar. Last year’s Holiday in the Wild is on the TV in The Knight Before Christmas, but in Knight the kingdom from A Christmas Prince (Aldovia) is mentioned.
With that said Vanessa Hudgens is also the star of The Knight Before Christmas and therefore in the shared universe of Princess Switch.
So, in conclusion the fourth Vanessa doppelgänger is The Knight Before Christmas’ Brooke?
However, thus far most of the “shared holiday universe” moments have consisted of other holiday movies being on the TV of other movies.