No, Palisade Giant's damage redirection effect will not work if it is not a creature.
614.9. Some effects replace damage dealt to one creature, planeswalker, or player with the same damage dealt to another creature, planeswalker, or player; such effects are called redirection effects. If either creature or planeswalker is no longer on the battlefield when the damage would be redirected, or is no longer a creature or planeswalker when the damage would be redirected, the effect does nothing. If damage would be redirected to or from a player who has left the game, the effect does nothing.
This stems from a more general rule:
120.1a Damage can’t be dealt to an object that’s neither a creature nor a planeswalker.