I wonder if she's embarrassed or taking it in stride

The stuff would be on iCloud even if had been deleted from her phone, you're right.

That video was made quite a while ago, back when she was was filming Winters Tale in late 2012 and early 2013. You can tell because of her hair, which is red here. She had to dye her naturally dark brown hair that color for the movie. Shortly after finishing she went back to her normal color.

So it's entirely possible that like Winstead she or her BF had already deleted this stuff and didn't know it was still out there. Or at least didn't expect it would be hacked so easily.