Identify Sea Urchin

[rosemoondust]

I have been getting into debate with my sister as to the species of my sea urchins. All three look exactly the same the only difference is that 2 are brownish-blue while the 3rd is a more bright blue.

 

[rosemoondust]

I am starting to think they are Pincushion Urchin. Can anyone confirm this?

 

[Wrassehole]

Either a tuxedo or pincushion urchin. Can't quite tell from the pics.