Rebounding: A good rebounder will retrieve the ball more often after a missed shot. Notice that height is already considered when a player's rebounding skill is displayed. A player who is 7'2" but has a low rebounding skill simply is very bad at positioning and will not get very many rebounds. He'll learn more quickly though...
Best Position: As with the DMI, this is a very rough guideline, and some would even say a meaningless one. You should play your players at the positions that make the most sense to the team, regardless of whether it is his listed position.
the game engine never looks at height