Identify these critters

I have three critters in my aquarium which I would like to identify.
Pictures of them are at www.w****chcock.com/aquarium.htm .

The brown coral is 1/2 inch across. I would like to know what it is so I can
give it the right amount of light.

The small white coral is 1/4 inch across. Since it doesn't have any
pigments, I don't think it needs light. Is that right?

I have three orange snails. The largest is a inch long. Underneath the
orange "jell-o" skirt is a shell that looks like a limpet. The snails body
is pale orange and it has a head and antenae that look like a garden snail's
head.

Thanks.