I can tell you with confidence that those drawings are way better than most 4 1/2 year olds! Very good and creative. The first one with the Teddy Bear and Frog is unique with its squiggle outline (to resemble fur, I think). That is terrific!
My AS son did not color unless I was holding the crayon in his hand and scribbling on paper for him; which I did when he was little, hoping he would do it on his own. He did, for about two seconds and then he would slip out of the chair and be on his way!. When he was about 8 1/2 he started doing some coloring by making a simple, large grid with a pen, then coloring in each box a different color with crayons, which he pressed very hard. He said it was to achieve a darker shade and richer color. When he was 9, he was given a spirograph and for a couple of years he made many elaborate pictures with it. He would not make the designs in the intended way, but would take out all of the plastic pieces and trace the outside of them onto large poster-board sized paper. Then he would connect the circles with snake-like shapes and randomly draw rectangles and squares over all. Then he would color, not according to the larger, outlined shape, but would color in every little shape where larger ones overlapped. It was really something; totally modern art.
Once, he was in the process of coloring one of these huge creations with colored pencils (which had to be kept perfectly sharp at all times) when he suddenly stopped and left it on the coffee table for days. I asked him why he didn't finish it and he replied that he had lost his red pencil. I located one for him but he refused to use it because it wasn't exactly the same shade of red that he had started coloring with (he thought I was crazy for suggesting that!). He was going to throw the thing away! I saved it and weeks later, he found the pencil; under the couch! He finished it and I am going to have it framed and hung up in his room.
His art is very colorful with overlapping shapes, but always geometric. His interest comes and goes. His art teachers have been very pleased. Not a prodigy, but better than average.
Right here, right now; this is where it's at.