So just as a general question, are characters that were in melee going to be so they are as close to their melee counterparts as possible? Or will there be some changes?
Most Melee veterans will be almost exactly like they were in Melee as far as their play style goes. For example, Link will play very much the same (sadly, without wall grapples) but with a couple of small, necessary boosts to his moves (and maybe to his physics) to make him a bit more viable.
Of course, some characters may see more changes than others (definitely refer to P:M Mario or P:M Pikachu on this), but the general traits of the characters that contributed to their play styles will be the same (heck, the changes will probably make the play style much more flexible too, ie. being a defensive or offensive Samus player).
Other characters really don't need to go back with much, like Luigi who has a superior Up B, Down B, and dash attack in Brawl.