Your Graces,
It seems this treaty is unpopular with most of you. I ask you to consider this somewhat plausible scenario.
In the Summer, Queen Isaelie sends her elves pouring into Elinie and Marcoesor, using Realm Magic to assist. The forces of humanity lose their first few battles. In the Fall, word reaches all of Anuire. In the Fall, I can begin to negotiate with Ghieste, Tornilen, Mhoried, Marcoesor, and Elinie for military access. If the negotiations go well, and I must remind you, just because two sovereign rulers decide they should go well, doesn't mean they will go well, then by the winter of the same year, the Knights will have permission to travel to the battle site. In the spring of the next year, the Knights will probably be on location, along with the rest of Anuire.
Be cautious regents, of course, but the Knights of Haelyn will do as the Conclave bids. If we can get these "legalities" out of the way now, then in the above case, the Knights would be fighting a full two seasons earlier, and may very well keep a Duchy intact. If any of you wish to sign a modified treaty, rather then this public, multi-lateral one, I would be glad to discuss it.
As for the question by the Countess of Illien, to be honest, Illien is not a gateway to other realms, so, for instance, we can reach Rosoene or Medoere without going through Illien. Illien itself has a strong liege-lord, and is unlikely to need a force of Knights to defend it. So given those two circumstances, I can see why you wouldn't be interested, as you and the Knights would derive little benefit.
And finally to answer the Marquis, the Knights would be glad to assist you, but we have no military access to get to you. Furthermore, the Conclave has not requested our presence there. While I do believe the Knights have some latitude in responding to a crisis, I believe the first step for you would be to ask the Pontiff for Conclave support. If the Pontiff agrees, then I will see what I can do about negotiating with all of the same regents mentioned in my "example" to get some men there. If your need is less "urgent", perhaps we can discuss the possibility of raising a force of Knights in Marcoesor, although given the realm's poor infrastructure, that may be problematic.