I can filter as picks or stars, but I can't pick or apply stars in LR on Apple TV. I guess if you filter by Pick, you are doing the same thing as filtering out rejected??? I don't have rejects in the same place as picks, so I can't test that.
Unless I can review on Apple TV and rate/pick, it's not very useful to me. I also don't see any way to set the speed of the slideshow. I can manually page through it, which is useful, and I can zoom and pan one click, which is also useful. (Panning is a little hard to control) But if I can set a pick or rating, I don't see how. I can only filter by them. I'd like to see the pick and stars that are used to filter available in the viewing section on the side as well.