Team Popplio 100%.
Here is what my general thoughts are:
STARTERS
I think it is refreshing how the colors of the starters are mixing it up a bit as well. We have a mostly tan grass starter and mostly black fire starter. Though, part of me wishes there were most of the original colors present, it is also maybe a refreshing change. It's hard not to notice that these starters are so different from previous starters and is definitely a break in the mold.
POPPLIO
I LOVE Popplio!!!! I think I found my new overall favorite starter! It's literally the cutest Pokemon I have ever seen. It has never been such an easy choice picking my starting pokemon. Just look at its little ball nose, cone nose, fin-paws, frilled color, and little smile! I seriously want one right now!!!!!!!!!!!!!!!
Evolution: Please do not get a "tough" evolution, I will be happy with a cute circus clown or an elegant circus performer. Though, I do see some form of physical performer, and therefore I predict (maybe water/fighting).
LITTEN
This is an interesting direction for a fire starter. It's pretty hilarious how Litten (which is an amazing name) has a little fire spike when it attacks similar to when cats hiss or are nervous. This is a bad little kitty for sure. (fire/dark typing confirmed).
Evolution: Is a Cereberus evolution too much to ask?!?! The coloring makes it pretty obvious it will evolve into a fire/dark type, but I think of Cereberus particularly with fire and darkness.
ROWLET
It is a funny little gizmo. I like his little bowtie and blank expression. As the grass quill pokemon I think he is a studious pokemon that will take little notes on his bark. I love the idea of a grass owl because of "paper" books and quill pens go well together. This is quite a different approach to a grass type.
Edit: Did not see Rowlet's typing!