Skycruiser.
Regardless of whether or not these are exam questions, I think that they are just as valid as any other question I have ever seen in pprune.
wrt the c of p movement above MCRIT.
Just above MCRIT, the first shockwaves will form, usually above the thickest part of the wings. These wiill cause an abrupt increase in pressure, which will reduce the lift generated by the area of wing behind the shockwave. This will cause the c of p to move sudddenly forward.
Continued acceleration will cause the shock waves to be pushed aft towards the trailing edge. At this stage it is important to note that the airflow over the area of wing in front of the shockwaves will be supersonic. The curvature of the wings behind the thickest point effectively forms a divergent duct, or expansion corner, through which this supersonic flow accelerates. So velocity continues to increase and pressure continues to decrease all the way to the shock waves. So as the shockwaves move towards the trailing edge, the lowest pressure and hence c of p moves back with them. The overall effect is that after its initial surge forward, the c of p moves aft to about the 50% chord point.
This is obviously a very simplified version of a complicated process, but I think it covers the essentials.
I'm not entirely sure about your other question, because it never rains in Dorset!!!