Like Velvet, Shanty's accent is a little hard to pin down to a specific country (if there's one directly related to it at all) but since she has a Jamaican flag on one of her alternate palettes, it's probably the closest thing we can place.
Oleander's flag was also changed since it was a little awkward being that Scotland is also technically part of the U.K.

Whoever the eight character is going to be, the devs said the were interested in having a grappler fighter. Just to keep in mind...