Thank you! I looked at your sketches, and I found them very creative. One of the hardest things thing with drawing characters, once you know basic anatomy, is to make them interesting and original, and I think you have that part covered
As for how to improve anatomy and poses, the best way to do that is to draw, draw and draw some more, using any references you can find. If you spend a lot of time drawing people, you will build a intuitive understanding of how to create your own poses.
You also need to differentiate between technique and knowledge. Try to draw a perfect circle, and you'll know what I mean. Likely it won't be flawless (at least mine are not), even though you know exactly how it should look. Drawing people is of course even trickier, since it's hard to know what the "perfect result" should look like (knowledge of anatomy plays an important part when you assess that).
I am far from confident when creating poses from scratch, without having anything to look at, so my goal right now is to practice at least some every day. We'll see how that works