My First Unova Pokémon was a Blitzle and I didn't catched it since I'm saving my Pokéballs for the new Starters. What about you?
I think the first I saw was a Sawk, when I was able see the catcher when it was offline for everyone else... The first I catched was a Zorua.
I don't remember what the first one I saw was, but my first Unova Pokémon was Minccino. Unless you count a Plume Fossil that I caught before that, but it's not really a Pokémon yet.
I don't exactly remember which one I saw, but I know my first caught one was a Minccino, because I just couldn't resist its cuteness. ;_;