Can Azir Sovereign move Reflection tokens if they've copied a unit?

Yes, Azir, Sovereign can move Reflection tokens that have copied a unit.

According to Rule 182.1.d and RiftJudge FAQ #9732, Reflection tokens are units. Since Azir, Sovereign's ability allows you to "move any number of your token units to this battlefield," and Reflection tokens are valid token units, they can be moved by his effect regardless of what unit they are currently copying.