Lady Emily is, in fact, still part kitten.
Monday night we booted both boys out of her bedroom, closed the door, and invited her to play with the feather cat teaser on the broad expanse of the bed. We tuned the play for her, keeping the teaser less active and often just crawling along the far end of the bed.
She took nicely to it, stalking and pouncing. She doesn't latch on like the Might Hunter does (a good thing), but rather tends to abandon the teaser when it's pinned under her paws and it turns out not to be edible. She does returns to the hunt after teaser "wakes up" again, and shows proper feline moves for chasing it down.
She does tire sooner than the boys, of course, but it held her attention as long as any play toy we've had in the house.