No they get plenty of screen time. Just not in every episode. When you have a cast this big you cant expect you favorite to be the star of every episode.

Well. Not Hook though. He's Benin getting a lot.

I actually fond this chart on tumblr displaying the amount of screen time each character has; Emma Hook Elsa and Anna have way more than everyone else; I'll hVe to look back at it and give some exact numbers.

I don't think they are. Just characters like Archie, Ruby...etc.

^^Yeah, Ikr! I mean, I really like Hook but it annoys me he gets so much more screetime than most of the others.
I think even if a show has a huge cast, it still should be able to find a way to not push aside important characters (Like Game of Thrones does and Lost did most of the time). Having a big cast is hard so they have to handle it correctly if they want to make the show really impressive imo :D