I can't see her rising through the ranks quite this swiftly...

The Seraphim Council is really something of an Old Boy's Club, when you get right down to it, and a former servant of Eli's would have yet another strike against them, even with the high placement of her current boss. (Dominc is often an ass, but he's a very high-ranking ass that a lot of folks are afraid of ticking off.) Added to this, I'm not entirely certain Rachael even has a Word yet, so it would be rather hard to get her on the Council. Traditioanlly, an angel would go from serving an Archangel, to getting their own word to promote within their master's Word, to eventually becoming an Archangel themselves. And then there's the whole period of time where the older Archangels eye the new guy suspiciously, as I recall the Archangel of Flowers is still considered a dirty hippie by most of the Council...

More likely some hard-working Archangel who hasn't gotten the nod yet will get the distinction. Never underestimate the power of a bureacracy.