From the trailer it kind of looks like a Maple and Cinnamon combo is definitely possible. (That's sounds good in more ways than one)
I'm sure we'll have another Chocola + Vanilla scene. Azuki and Coconut will probably get the shaft, but who knows.
I'm hoping they step it up and put a good amount of new content in general. Backgrounds, music, etc. The second game was great, but it felt way too much like the first with so many things recycled.
I will say that Sayori's art continues to get better and better. I know trailers are always dressed up, but if you compare the art from the first game to the trailer it's even more detailed and just seems more HQ. Spring can't come soon enough...