I'm curious where Australian rock comes from- is it aquacultured or wild harvested? Looks to be really full of life- somebody did a good job collecting it!
Everything looks excellent and don't worry about the algae- it will work itself out.
If the blue star is a linckia it eats the film that develops on the tank walls and rock- needs a well established tank to survive.
The feather star (is that the same as a Basket star?) I know nothing about except how hard they are to keep going.
And the urchin may be bad news- they graze on corals and coralline algae.
Do some research on Google and try to find out exactly what species things you have so we can figure out how well they may do.
And I'd respectfully caution you to slow down on adding any more creatures- things need to time stabilize quite a bit in a new tank. Letting it simmer for a few months is the best thing you can do- maybe add a clean up crew of snails and hermits, but nothing else.
Most of them are hitch hikers except the featherstar, but i was going to add some hermits as you say once i get the skimmer up and running.
Should i take the urchin out or just watch it?
Na, the Maze and Hammer i brought a few days ago.
The others are hitch hikers.
I got some more info on that urchin and its a bit iffy at the moment, although its cleaning the diatom off the glass, which is good.