I have 3 urchins in my tank, a black long spined, pencil and another spiney(2'' long reddish spines) along with a 6 line, yellow and a cleaner wrasse, not to mention a lot of other live stock, but these fish you questioned about in my limited experience don't bother each other. The only problem I have with the long spined urchin is it seems to enjoy munching on green star polyps and all the urchins like to wedge themselves into spots that are tight and push some coral and rocks over or off a ledge. But all in all they are quite cool and the wrasses are awesome.
Good luck.
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Greg
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