Hm... I'd keep your cat out of the room with the fish tank to be honest. You wouldn't wanna risk having a shrimp on the frogbit, getting scared, and jumping out of the tank. Also, I've read many horror stories where everything in the tank would die if the cat had a lot of kitty litter stuffs on its hand.
Hope the shrimp enjoy their new home
! More pictures when they color up some!