In the above image I circled three impact sites on the northern rock hard crust.
I found two blurry images which were taken at further distances so they are not as clear but they wrap further around Charon's east and west edges and reveal some relevant information.
In this view we are elevated more toward the north so we don't have a good southern view but we can see the impact which hit at the 2 o-clock site. Just above that impact is a series of impacts in the northern hemisphere with their relative gray color variations. The center of the impacts are darker with a splatter of white debris.
I have circled them in this image.
These impacts become a gray tone colorized frame of reference identifying the rock hard ice mantel.
If you look at impacts on the southern hemisphere none of them display this signature of dark central damage with white splattered material as a matter of fact in these blurry images you can't see any impacts on the smooth southern hemisphere which was liquefied. Since the south was liquefied it adsorbs impacts more than it splatters their debris. This means (in these blurry images) impacts on the rock hard ice crust of the north leave clear evidence of the impact while impacts on the smooth liquefied surface don't.
This image is from the eastern right side of Charon. In the image above the Pop zone is on the right in this image it is centered and left.
So the two large impacts in this image are around the right back side which can't be seen in the large image above.
Since these impacts look just like the ones on the rock hard northern hemisphere, these impacts occurred on rock hard ice not soft liquefied material.
I have circled the impacts in this image.
One impact is in the north the other is in the southern hemisphere. This means the back southern hemisphere was not blown off just the side facing Pluto.
That means the only area liquefied on Charon is the part we can clearly see which is facing Pluto.
I suspect the gravitational pull of Pluto coupled with the diagonal fracture along with the shock waves from the impact at the north pole which created Mordor blasted a quarter section off Charon and like a shotgun blast fired this material towards Pluto.
Pluto's gravity helped direct the blast toward itself.
That means this southern section area of Charon that liquefied is the only area of Charon that dislodged and blasted away towards Pluto.
This would have focused the blasted debris toward Pluto at the side facing Charon due to Pluto's gravitational pull increasing the effect and damage created by this dislodged material.
Therefore, I don't think the whole southern hemisphere of Charon was blasted away just the quarter section facing Pluto which can clearly be seen in this image.