In the third picture: those clusters of white bulbous tubes in the middle are most likely tunicates. You can see them in all three pics. Very cool animals.
Those all look like vermetid snails to me, even the ones you called tunicates. See how they coil at the base? Vermetids are an unusual type of snail that initially coil but then form meandering tubes similar to some polychaetes. This small species is very common in tanks often to the point of taking over. Here's some info on them: http://www.reefkeeping.com/issues/2005-01/rs/index.php