Yes, another carrier. Every animal should have their own carrier.

Yes, another litter box, Vets will tell you 1 litter box for every kitty plus extra one. Two litter boxes work ok for 2 pets.

Yes, food... if the new guy is a kitten he will need food made for kittens. Their tummys can't handle adult cat food.

Yes, water dish. Never can have enough of them around for guys to get a drink.

PetSmart great choice to look for pets, Kinda partial we got Thumper there

Good Luck