I forgot to reply to one part of your post.

ectoterrestrial wrote:
Question:
Would one expect transform faulting if there were a wedge shaped plate like the striped region?

Alex writes:
As long as strike-slip dynamics are possible along the plate's margins, I do not see why not. Even assuming that the MAG/ER data represent a crude approximation of a plate(s), the absence of transform faulting in images of the region casts doubt on the interpretation. That said, as the MAG/ER team noted in their paper in Science, this does not preclude the evidence being buried deeper in the crust or, if nearer to the current surface, having been erased in the highlands bombardment. We really need to press studies below the surface.