Storm:
Stormy Storm, Big Blue since he's a blue cat, Jelly Face because he gets jealous, Grumpy Old Man when he's acting grumpy, Big Kitten when he's racing around like a speeding bullet

Sunny:
Baby Sun, Sunzy, Squeakers or Squeaky because he makes high pitched squeaky meows, Goofball, Mr. Sun, Sunster Riley

Sky:
Mr. Sky, Fluffy Sky, Bush Baby because of his big bushy tail, Sky Baby

Starr:
Peepers because he's always watching me with his big blue eyes, Poopers and Mr. PoopoopyDoo because of his poopoo problems, Chubbers since he's gained so much weight, Pillsbury Dough Boy since he's gained so much weight, Little Boy, Baby Boy

Pearl:
Pearly Girl, Missy Mam, Pearly Butt, Little Girl

Ziggy Stardust:
Ziggy, Zigs, Zigster, Ziggy The Piggy because she has a huge appetite, Baby Girl, Bush Baby because of her big bushy tail, Sweet Girl, Sweetheart