Worm thing is vertnid (sp?) snail. You can glue the tube shut it annoys the coral.
Im not sure what is on the clowns, but it could be from the rough housing. Clownfish disease usually is first seen with mossy stuff around the gills. And it looks too large to be ich to me. As long as they are still eating, there is hope they will bounce back. If you added them when they were both about the same size there can be a lot of fighting as they figure out who was going be the female (dominate one).
And the lighter one is most likely the male, the females are darker and larger.