Seeking a fair way out of hyphenated names

Your child's primary identity belongs to the child.

So far, your child, whom I will call "Brittany Clovis Stevenson-Glockenspiel" is mainly the symptom carrier for her mommy and daddy's unwillingness to identify as anything other than their individual selves.

One way out lies in the symmetry of your growing family. You could give one child your surname and the other your wife's. This keeps everything fair, with each of you clinging to your respective separateness.

I take issue with your characterization of a middle name as being some sort of identity exile. Because you wrote, I vote for your name to go in the middle.