The tapeworm comes from your cat or cats eating a flea so it's possible only one has a tapeworm. However, the vet will probably recommend they all get it to make sure. The "bits of rice" are the ends of the tapeworm as it sheds them. If you see them on your cat's behind, you may see them moving but they dry out quickly and can't infect anyone.

The fleas in your nice warm home are those that have hatched from eggs laid anytime in the past year or two in your carpet or furnishings. Sprinkle 20-Mule Team Borax over your carpet and don't vacuum for a few days. Keep it down, if you can, on the edges of the carpet by the walls and around the edges of furniture. Use it under the cushions of your sofa and on your mattresses. Sprinkle it on the carpet after each vacuuming for a few weeks. It's a laundrey softener and you'll find it with the detergents in your supermarket. Don't sprinkle it on your pets. I've been doing this for nearly 20 years whenever I've found new cats have brought in fleas and it works better (for me) than anything I get from the vet. Since several of my cats go outside my vet is always surprised that they don't have fleas.