The bird has a great design among all of its evolutions, and honestly the best designs of all 3 starters. It doesn't look like it's just getting bigger, and each step in its evolution introduces or remixes an element from the one before, making them all fairly unique. Would definitely pick this guy.
The fox is one of the weakest of all 3, since nothing really changes much between the evolution stages. I hate to use the term, but it is literally "just getting bigger", since all that's really happening is just adding more to it. On the contrary, there's very little difference between the 2nd and 3rd stages. Rather than focusing on making them have good poses to tell them apart, try giving them all t-poses and seeing how similar they really are.
I can't think of much to say about water guy, but it sort of falls under what happened with the fire starter. There's very little going on, with the only thing going for it is that it actually looks menacing, like old-gen Pokemon.