Nintendo's Japanese version of the collection will have Kirby's Dream Land, Kirby's Adventure, Kirby's Dream Land 2, Kirby Super Star, Kirby's Dream Land 3, and Kirby 64: The Crystal Shards (Jordan, it looks like you got your wish!).
Of course when a localization announcement hits this could change, but everything seems incredibly reasonable for a stateside release so far. Also, much to my approval, there's the added announcement that the collection will have all new mini-games included in the package. Thanks for listening, Nintendo: this is what you should have done for your Mario Collection.