The Old Testament law in question deals with how a ceremony is conducted. So it is obviously and explicitly a ceremonial law.
The passage in Hebrews in the New testament speaks of a spiritual relationship with God; all of the ceremonial laws point to some sort of spiritual reality. Also, "actual parental marital status at birth" is irrelevant to the spiritual reality spoken of in Hebrews 12, as John 1:12 makes legitimate son-ship available to anyone who receives Jesus:
John 1:12 "But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name:"
Perhaps you should exercise a little charity when interpreting the bible: http://philosophy.lander.edu/oriental/charity.html