Regarding the first image, the way I draw the hip area and legs in general is pretty exaggerated, I remove a lot of muscle and curve the bones. The left of each set is more correct if you’re aiming to be more realistic.
The second image is just how I personally stretch legs into different body types. The third is one of my most generic poses and some feet. I approach the bottoms of the feet the same way I do hands and I make toes by just overlapping the little circles. The fourth image features some attempts at different positions I don’t show as much, an area I still have to work on myself.
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I’ve still yet to recover from my recent lethargy, so this was all I could think to do… but I hope this is of at least some use! Sorry! :(