Greg,
I agree QT'ing everything wet, but in your case since there's no fish yet, just put the inverts in. If there's any ich cysts attached to the shells of the inverts (possible), then they rupture, the parasites will die because there's no fish to host. I don't think you'll introduct anything bad otherwise.
Even though you had cured rock and didn't see an ammonia or nitrite cycle, there are other "cycles" that your tank will go through, and various algaes will come and go. If you're seeing brown stuff all over your rocks, it's likely diatoms, which will disappear as fast as they appeared.
Hope this helps.