Equations are correct, but only for the body factor. Actually, you must consider body factor to get the right set of equations. Also, the minimum CMR could be limited by the Vgs8+Vtp.
hi
finding the icmr of each stage is not a good idea because u will have to give feedback to each stage in order to find it. instead provide a feedback to the whole amp by placing a large resistor between output and the -ve input and a large cap between -ve input ang ground. do the dc sweep and find the extreme ends