2 quick questions after re-reading this thread,
1 - Wouldn't the Sarna Commonolity be better if named the Sarna Supremicy?
2 - No Marian Hegemony?
Well, it's earlier rather than later in terms of reformation, so the Sarna Commonality is closer to the proto-nation's original incarnation. However, if the faction developer of the Sarna wants to change it to the Supremacy, they're welcome to it!
The Marian Hegemony is a relative newcomer to the Inner Sphere, formed in the 31st century. If a faction developer wants to break apart or create the Marian Hegemony, that's more than possible.