Hi jomer,
The first two pictures above are both examples of colonial tunicates. These are common hitchikers on live rock. They are filter-feeders, subsisting on plankton and even on bacteria in the water column. These are among the common cryptic creatures growing in and under live rock, which help a lot in keeping your water clean. (You would be amazed at how much water turnover they actually perform. Because of that, a famous US aquarist Steve Tyree uses these types of creatures for "cryptic filtration" as part of a very-philosophically-different three-zone natural filtration system.)
Not too sure about the third picture. It could also be some form of Ascidian or Sea Tunicate or Sea Squirt (they all belong to the subphylum Urochordata, but these names are used interchangeably, depending on genus, without any logic
). Or they could be the beginnings of some soft coral?
Phil