IGN is saying that all three games will be included in full, all with trophies.
http://www.ign.com/articles/2012/09/20/tgs-kingdom-hearts-hd-remix-coming-to-ps3
In any event, I'm psyched! My favorite series and I would very much like to play the main games again, and finally get a chance to play the handheld games. I will definitely get this and 2.5 whenever they decide to release that. Hopefully 3 won't be too long after. =D