First of all, these are great! The anatomy and proportions on all of these are very solid. It looks like you do lots of short strokes when you draw. Have you tried doing one quick stroke? For your sketches I actually kind of like how it looks, but if you want to clean them up more try using less strokes. I recommend using a brush pen. It makes you think about your linework more because there is no undo button. Keep up the great work!
I'm not a fan of the "manikin" method some art schools use, it makes the figures look stiff and you're not really learning how to draw organically. I only use it for some extreme foreshortening because it can be useful in that case.
I think you should try to draw figures with as few lines as possible, try to get the force lines with just one gesture, follow the curves of the body with one line. You did it with the 7 min. one (well, most of it) and in fact it looks better and more natural. Maybe lower the time, make it like 3 minutes, that will force you to become faster and more confident in tracing the body with only one line.
Like the poses overall, I have to agree that your watercolor one is lovely! :3. I can't see your line of action as Mike has already pointed out. Incorporating a line of action will speed up your process and make your poses more life like. Think about what line would best represent this figure before you put your pen to the paper. Drawing is seeing, we don't draw to see - we already have the picture in our head (that's what I try to do anyway x) Good job anyways!