Urchin ID

[ThunderGoose]

My live rock (TB Saltwater) came in with several urchins. This one has doubled in size since I first noticed her (2 weeks, maybe) - she carried shells around and has pale spines. Any ideas?

And is this one a black longspine? She doesn't carry things around and she's growing very fast, too.

She used to fit in a crevice in that rock behind her. She arrived either June 12 or 21 (on live rock).

 

[Gexx]

First one looks like a shortspine urchin or a type of pincushion. The second is a Diadema urchin i believe