@ArtMelC First of all, you got a really lovely drawing style. The issues that I can see is on the structures of the drawing.
I drew over your drawings a bit. I based everything else on pose 2, because I think that drawing was really successful, the only issue is that it seems weird and unnatural to me that the side that is carrying the bucket is the one that has the leg in the air, when it should be the leg that is carrying the weight of the pose and bucket, not sure if it makes sense but try to do that pose by yourself, with the leg that's in the same side that you are carrying the bucket in the air and the one behind in the floor, you won't be able to find balance.
Pose 1 is a little off with the width, I made a fast comparison with two lines in blue.
Pose 3 also felt kind of unnatural to me. Your torso seems to have a C shape that goes against the direction that the kid is running, but I think it makes it looks like it because of the lines you added to the t shirt, it makes looks like the tshirt is getting air blowing from behind. Also, the leg that is in front instead of just going forward, it looks like it's to one side; to make this point clear I drew a small figure in blue on how I feel the structure of your drawing. I also added a new drawing of the kid running with the help of a reference I found in google.
I think you can see these issues if you zoom out a little bit and flip the canvas. I added your illustration like that in the far right of the images.
I also recommend you to practice about construction. I'm sure there have to be videos here about it. Draw a box also has really good exercises for this.