Good stuff! As long as you are starting to practice and keep on doing it you will improve. Marc builds on these assignments a great deal as time goes on.
One of the biggest things with these is making sure that you are noting the position of the hips and where the weight of the model is balanced, there is a lot of information to be gained just from focusing on that. You really noticed it in 3 and 5, but it does exist in all of the other images to some extent.
On number 2 your wrote "How?" what are you referring to there? For some reason I cant expand your image to see the other notes, but I am happy to help out as much as I can.