Ok for those who can't see the similarities between these possible evolutions here's my view:
Tsutaaja is pretty easy. First it's a snake with legs and arms, a neck collar, and a leaf on it's tail. It evolves and it's arms becomes smaller and it's legs become more fragile. It gets a little sleeker and it's collar grow out. Then in the final form it loses it's legs and arms and becomes slim and sleek (similar to what happened to actually snakes) with a leafy tail. The collar around it's neck grows out which makes it look like some type of king snake or something.
Mijumaru was a little tricky at first but I kind of see it now. Notice how Mijumaru has dark blue ears, a white face, little dots on its face, and a light blue body with a shell on it's belly. Also notice how it's feet are flat. Then it evolves and it's body becomes blue, grows whiskers from the dots, it's lower body becomes dark blue with two shell on it's side, and it's feet get longer and flat, and so does it's tail. Also notice that little spike on top of it's head. Basically we see it's becoming more and more aquatic. With those type of feet walking on twos becomes harder and harder. Then we see it's final evolution which finally becomes quadrupedal, giant otter. (An actual species of otter.) It has fully grown whiskers, has a dark blue body, the shell on it's sides has covered most of it's body, including it's tail and the thing on it's head grew out to what seems to be a conch shell. So basically Miju's final forms is just a quadrupedal otter.
Pokabu's is the easiest. As a Pokabu it's seems to have a black bandanna on it's head, while wearing a black diaper. Also that yellow mark on it's nose resembles a flame on a lighter. Then Pokabu evolves and becomes bipedal with black tights on similar to a wrestler. The final evo looks as its it's wear a championship belt and has flame coming out of it's nose. Also notice how Pokabu's tail looks like the lit end of a bomb, then when it evolves tail tail look like the bomb has been lit and it's almost ready to explode, and then the final evolution has it's tail looking like the bomb just when off, maybe that's which there's fire coming out of his nose. Not too sure on that last part.
Anyways that's what I think. Hope this helps some people.