Wedding-ed- need ideas!!!?

My sister is getting married. Fantastic. I am her MOH, we have another sibling, born a male, living as a female. We don't want anyone to feel exempt, but they have chosen 2 Groomsmen and a Best man nd 2 bridesmaids and a MOH. She is worried about symmetry. She doesn't like the idea of more women, but they are grasping at the idea of another man. What ideas do you have? Has anyone dealt with this before? What did you do?