ID needed

[Myka]

1) Hydroids (not good)

2) Some sort of macroalgae that you prob won't get an ID on. Most macroalgae are great in a refugium, but can become quite the nuisance in the display tank due to their often rapid growth.

3) Coralline

4) Bi-valve of some sort. I have a few of those, and haven't bothered to find a specie or genus name for them. If it is still alive it is a beneficial filter feeder.

5) Bryopsis starting. Not good.

6) Vermetid snail. Particulate feeder. Not usually a pest, but may bother some corals they contact.

7) Can't really tell from the pics, but you might be on the right track with your Pistol ID.