Hi,
When I first came online in 1996 one of the mailing lists that I belonged to posted a definition of mulatto. The description included anyone who did not have Aryan features, i.e. blond hair and blue eyes, etc. I think this might also fit in this circumstance. I for one, think that anyone who did not look European was considered a FPOC if they were not a slave regardless of nationality.
Some of my Thomas family from VA who settled in PA in the 1840s indicated on their draft registration cards that they were Syrian and Ethiopian. I am not sure they were telling the true, but after doing DNA testing, I think they might have been.
I have seen members of my and my husband's families go from white to mulatto to Negro.
Linda