Is it safe to apply cat flea shampoo and powder to the following:?

No - the products you are going to get are NOT safe for use on nursing moms and will poison the kittens. Kittens cannot have any flea products applied directly to them until they are 8 weeks old. The only exception to this is a product your vet will have. If mom has fleas, yes the kittens will have fleas. The only safe way to treat everyone - short of taking them to the vet - is to get Advantage or Frontline from the petstore, and apply it to mom only. Anything else is NOT safe for nursing or pregnant cats, and will likely poison the kittens. She needs to be flea treated as fleas can quickly suck the life out of kittens by causing flea bite anemia. Your best bet is to pack them all up and take them to the vet but if you won't do that, then get Advantage or Frontline for mom.