I have a theory. At this point (and I acknowledge much more testimony is to follow, so this is preliminary), I wonder if Cassidy opened the closed master bedroom door, and entered the room after Jason had bludgeoned Michelle. He was in the closet getting new/clean clothes. Cassidy walks around MY's body, through a ton of blood with her socks on to find her daddy in the closet (remember, she had socks on when she was put to bed, per Shelly Schaad).
Jason is surprised that she's awake. She goes into her bathroom to wash up, taking a sock off on the way. Jason comes in to get her (with towel/washcloth, which is why Cassidy thinks later that MF needs to get a washcloth for mommy?), but picks her up, and she is upset about her mommy, and kicking/resisting due to what she has seen. Her little feet are hitting the wall. She or he takes the other sock off, but she still has blood on her bare feet because it soaked through. That explains both the "bloody footwear prints" as well as "bloody toe prints" on the lower part of the bathroom wall.
I just hope he didn't take her outside to the back spigot/hose to clean her off. It was cold that night. But I think he might have, based on what has been testified so far (no blood in the sink or tub). (But still, he had to have cleaned up the sink, because there must have been some blood since she had got up on the stool already.)
Then he took her upstairs, drugged her and put her into the bed, and closed the master bedroom door when he left, keeping the dog out of the room. Cassidy woke up later and went in to see her mommy, by which time the blood had dried.
I reserve the right to change my theory as more info unfolds.