That’s great stuff! Side view of the body I also found tricky, lots of rhythms that don’t seem too intuitive on my mind at first
As for the muscle, I am mot entirely sure which you mean. There’s one that crosses over from the scapula all the way down to superficial facia and the proximal radius that starts with two heads (biceps brachii, thats the one that supinates or makes your palms face up when the elbow is flexed). That’s the more anterior or superficial muscle of the arm. Then, right under it, hugging the the middle of the humerus and inserting on the proximal ulna you have tue brachial muscle, it’s under the biceps and is actually the most important muscle for flexing the elbow joint (closing the angle between the arm and forearm.
Additionally to those two, one of the muscles of the forearm crosses over the tendon of the biceps brachii from the lateral side of the humerus towards the distal radius (brachioradialis) this one helps flex the elbow and is best seen when the forearm is pronated or not entirely supinated
As for palettes, this is a hard one! Haha, i like both the second and third versions best but somehow feel the last is coolest. I can imagine her being some sort of sci fi valkyrie defending a green friendly civilization in a far away galaxy
Keep it up!