Three hitchhiker ID questions in one photo!

[billygalaxy]

What are the white upright things?
What are the small fluffy anemone-esque things to their right?
What could be building the sand tube on the bottom right of the rock?

 

[MoshJosh]

First on is a sponge, I like this particular type of sponge though they are not super prolific in my tank.
Second I would guess some type of sponge, but that is really just a guess.
Third I would guess spaghetti worm.

 

[EeyoreIsMySpiritAnimal]

Third is likely not a spaghetti worm. Probably a Phyllochaetopterus.