From what I can see, there are a group of features, Homeplate being the largest, that generally consist of a flat circular area sitting a bit above the surrounding surface, all of which are at essentially the same elevation, often filled in with a lighter colored material.

I'm guessing that what's going on is you had a layer ("Fenway" we'll call it) that was once continuious, with craters made in it when it was the exposed surface. That layer is later buried by something else. Still later the overlying layers have been removed, and the Fenway unit starts to be eroded. The crater rims are more difficult to erode than the rest of Fenway, so you end up with high standing circular features, partially filled in with whatever was on top of Fenway before (or maybe just with accumulated and considated dust?). Further down the the little valley (i.e., to the right) even the crater rims have been eroded away, while on the hills the layer with the cemented/filled craters is just emerging.

I'm not sure if I'm reading correctly which layer is hard and which is soft, but the pattern sure seems to me that what we're seeing is the exhumation and then erosion of craters in a stack of rock layers that erode at different rates.

My SWAG for the day at least.