The two biggest possibilities are
Amyloodinium ocellatum or
Brooklynella hostilis (both?). Given the decription and speed in which they passed, it could be either. With this species, the more common ailment would be
Brooklynella hostilis, at least let's hope. Any/all anemonefish should be treated for this parasite (Brook) prophylactically as part of the normal
QT procedure.
Since the Tomato clowns did not go through a QT, the tank may be infested with a potential pathogen. If
Brooklynella hostilis, you may get lucky and none of the other fish will be affected. If
Amyloodinium ocellatum, they will
all need to be treated with copper. Considering your fish types, that must be Cupramine but at no stronger than 0.4 ppm. You would also be wise to perform a prophylactic series of formalin dips. There is no way for you to know which without microscopic examination. The Symptoms to watch for are....
Fin clamping, rapid breathing, flashing, swimming in front of water apparatus, severe color loss, jaw agape, excess mucus from the fish, stringy slime, a gold sheen, cloudy eyes, hiding and sometimes surface gulping.
You must set up a QT ASAP and be prepared for the worst. It's impossible to say which of the two parasites killed your fish but I would lean strongly towards Brooklynella. As for your invertebrates, these are fish only paraasites so they are not in any kind of danger.
Some reading for you...
http://www.reefkeeping.com/issues/2004-10/sp/feature/index.php
Cheers
Steve