This is what my vet said:

The eyes on this kitten are not cataracts. A cataract is deep within the eye lens causing a cloudiness inside the pupil. This is a cloudiness of the cornea- often viral induced in young kittens from calici/herpes/chlamydia virus'. I am pleased to hear that it is improving- generally these get worse over time especially without treatment. I think this kitten could benefit from topical antibiotic eye ointment and oral antibiotics as well for secondary infection and corneal edema.

This is exactly what I have been doing, so I will continue the treatment. Should he get worse or stop improving, I will get different medication from the vet.

3 of the 5 kittens will go to the shelter tomorrow (they ARE property of the humane society/shelter, just in foster care) for adoption. They are ready, eating dry food, clean themselves, use the litterbox, drink water and refuse the bottle. That's my sign!

I will keep the little male "calico" back because there is still a little bit of blood in the stool, and also to keep Rusty company, who I of course will keep here until he is either completely healed, or somebody offers him a home including all the treatment he needs.