They have an expertise that would be key indeed or else the Seal Team might be lost the same way as Tytalus was when he faced the Fey.
The Merinita of Thebes aren't part of the Season courts as they typically are aligned with the Greek Faerie Gods. They might be convinced to join the epic event of restoring the founding covenant of the Order... but you'll have to learn Greek to convince them 
W
That pic needs to be added to the Meme thread, just with the title: "The Order of Hermes Seal Team:"
Something similar happened in my Saga, Durenmar was swallowed by a Faerie Regio drowning out the Magic Aura, and King Fir crashed a Tribunal. There was an immediate attempt to extract survivors, which was mostly, in my saga, predominantly Flambeau, because they were the quickest to organize, and the Tremere were at the time very occupied by the Mongolian Invasion.
All Flambeau members of the unit that entered Durenmar were members of the Legion of Mithras, which is one of most capable and organized hoplite lodges in the Order (if you use the cult, anyway). There was no stealth there, but the hoplites understood that they risk being overrun if they get into protracted fights, so it was more of a shock & awe operation.
The following events will see the participation of more houses, and I largely agree with previous posters, my the top dogs are, in no order of capability:
Considering that the attack on Durenmar is a symbolic attack on the entire Order and a crisis that just immediately gives eryone Schism War PTSD flashbacks, I assumed that some of the more esoteric elements of the Order came to play. In my saga, a Fenicilian Ritual was deployed alter the Durenmar Regio so the hoplites stood a chance of getting out. I'm fairly confident that a very few ancient magi who may have personally witnessed the Schism War are are skulking about the Order still. Getting this old is not really compatible with throwing yourself at such crises personally, but I assume one of them at least would quietly nudge events in the correct direction by bringing long-forgotten facts to the Order's attention or applying some soft power to make cooperation more effective.
What I was thinking about a lot is: how many hoplites are there in the Order? This would of course depend a lot on the House, with Mercere probably having none, while perhaps a significant chunk of Fleambeau being, or at least acting like one. I was working with a general number of 5-6% relative to the total population of the Order - it's a lot, but then the Order, like the general perception at that age, is pretty martially minded.
While being a lot, 5-6% is also not terribly many people in absolute terms. It's a small enough group that with a decent awareness of the Order's political landscape, you can concievably know, or at least vaguely recall the name of every hoplite. It's also few enough people, that if you remove a from the equation due to being involved in or recuperating from some conflict, being in twilight or otherwise beyond reach, etc., you get a small enough group that they could concievably sit down together in a hall to discuss the situation