This is a subject that always bring much discussion..
I would say in general it would be park where for any of the restaurants the op listed, but if you were going to California Grille or Citrico's or V & A, which requires a jacket, I would say Resort casual is the way to do. Pants and a collared shirt and a nice outfit for the ladies, capri or slack, skirt, etc. are recommended, whether they are enforced or not, it is up to Disney.