They certainly seem to be.
Is the hearing system ordered toward hearing? Is the reproductive system ordered toward reproduction?
Yes and yes.
If not, then is the act of attempting to reproduce with one's ears equivalent to attempting to reproduce with one's reproductive system? Would the former activity be disordered and unnatural?
No and yes.
Disordered, unnatural, yes. Should it be illegal, no. NO ONE'S RIGHTS ARE BEING VIOLATED.
Generally speaking, what about the person engaging in unnatural acts? Is he harming his life? Why does he have a "right" to harm himself? Where does it come from? Is his right to life violated? Does the harm to his life, health or soul resulting from such acts represent a loss to others as well as himself? Why does he have a "right" to harm or diminish society? Where does this "right" come from? Define rights.