In the player companion Humans of Golarion at the start of the trait section it states the following: "The following traits provide new ways to customize player characters hailing from the different human ethnicities found on Golarion. These traits can be taken by anyone of the listed ethnicity." So my question is do you have to be human to be of that ethnicity? Can you be a kitsune from Varisia and take a trait specified for varisians?
No, race traits require you be of that race to take them.
There are regional traits for areas though, see Varisia Birthplace of Legends book.