Since you're in the North Metro - Grandma's in WBL would be an option. I'm not a big fan of their frosting though. You could check what the options at Sam's Club would be to fit the number of guests you're having (their whipped icing is pretty good and better yet doesn't stain! even with the darker colors).. As for catering - I'd go with one of your favorite restaurants. I know one year, silly as it sounds, we went through the McD's drive-through for Happy Meals for the kids... They loved it and it ended up being pretty cheap!
Re: First birthday