Oh dear, it sounds like an Asterina Star. If it's legs are "stumps" and varying lengths it is. If you're not keen on getting rid - as it might be an algae eater, you're best to keep an eye on it. If it tends to stay away from your coral its an algae eater. Personally, again, I never risk it. Note they drop a leg in order to multiply.
The sessile thingy sounds like Tube Worms / Fan Worms.
Not sure about the last one, sorry. All I can think of is a Spoon Worm but that's a wild guess.
agree with pajawa on the corals, nice freebies you got there, they will open up when they're settle and depend on the cycling if you're lucky not to have high ammonia etc. the second pic I'm sure is a manjo aiptasia and need to get rid of it now before it multiply. there is a new product out now called aiptasia X from Red Sea. It very simple I've used them as I've a few. Here is a video of it on youtube..
Hmmmm will deffo order some of that aiptasia x asap.
I've altered the flow of one of the power heads on the advice of pajawa to slow the current a little around the zoas and they've already started to open a little, the button polyps, two out of the six I can see are fully open.
Just seen something crawling along the live rock at the back of the tank.
Too small for a photo so I'll do my best to describe it, it has the body of a slug, is cream/yellow in colour, just behind its head (where there are two antennae) there is a "shell" resembling the back of a wood louse. Its camouflage is excellent, the shell is the same colour as the rock and has patches of red mimicking coralline growth. Any ideas???