It would explain why she has 2 appearences and her tricky nature (because she definetively knows something else that she is not telling us). But, as a shapeshifter, being isolated in the middle of the swamp doing what exactly?
From my point of view, I think the shapeshifters have a goal and a leader, since they are working together and seems to have the same interests in Northcrest royalty.
In my opinion, the shapeshifter or is someone from Bareshade, or is someone close and related to Northcrest in some way.