CMOS source follower with 2 in series
The best way is to draw the small signal equivalents of each of them. After some practice, intuition will help to tackle them. I have attached the picutres of my worksheet for the first three cases (circuits 1,2,3). The others can be found similarly. I have kept the variables as gm and gds with suffixes 1 or 2 indicating the mosfet numbers. They can suitably substituted using the variables Kn,Kp, W,L respectively.