Let's be careful with memory here. Let's say for the player sprite, we use two sprite layers, and have two frames of animation, per animation state -- that's four sprites each for walking left, walking right, walking up, walking down, attacking, blocking, etc.
But we can only be in one state, that is, have one animation playing, at a time -- so why don't we only keep the active player animation in memory, and swap out using the REU between frames if needed?