OOC: Yes, the failure of Marie's glacier transformation could be a...very large issue. Though maybe if the drakes could fly the group in (their flight wouldn't be disrupted) the glacier could be dropped behind while the party flew over the suddenly-manifesting ice.
The Arcane Connection point is one that Vares would have/needs to take into account. The reason for this is that, with Antonio's permission, he would have taken a page from Carmen's journal (or another appropriate item) as an Arcane Connection to her IF the Arcane Connection remains active/reactivates when in the same plane as Carmen. Vares can use it to establish her general location and maybe, just maybe, communicate with her (depending on if her Parma is up or not). He'd also want Arcane Connections from the Grogs, as Esteban instructed. Then there's using one of the Arcane Connections that Khyrom left behind (starting to 'fix' them in the lab should have stabilised them; theoretically, there is up to a ten day limit after the Lab work was started before it has to be resumed, which allows an extension of the transient Arcane Connections to that time).
He can Flex one of his spells, "The Far-Prying Eye" to see wherever he has an Arcane Connection. This may give him a literal view of their objectives. Barring that (e.g. if the target has serious MR against it), he knows another spell, "Strings of the Arcane Connection", which he has used before to triangulate on a target. He can see the strength of the thread and its direction. Moving a measured distance, he can take another reading and use it to triangulate. Varying altitude can help with elevation, though that really doesn't work very well over long distances. Once in the Arc of Fire he should therefore be able to quickly learn the direction and distance to Carmen and perhaps Khyrom. Since the spell works on the Arcane Connection to the target and not the target, observing the connection, it doesn't have to overcome Parma or MR and should still work (it has before). This should accelerate the progress of their search.
Vares will need to make a formal request of the other Magi in the group. His magic is exceptionally suited to gathering information and keeping tabs on everyone, as well as making teleport jumps. With the permission of his fellow Magi, he will be using periodic Flexed invocations of the spell "The Far-Prying Eye" to see what's happening once the group splits up, and Flexed "Whispers on the Wind" to hear from them. He has the ability to cast CrMe spells to communicate with Grogs or CrIm if desired (CrMe has the advantage of being silent). Thus, he can help them stay in communication with one another and develop some idea of what is happening elsewhere, coordinating their actions. If he can establish a fix on Carmen he may be able to tell her than the party is coming.
An alternative, if Arcane Connections work as long as the user and target are in the same plane, is for Vares to give each divided party a 'stick' linked to another in his possession. This will act as a targetted Arcane Connection on the object. In effect, they will know that he is there, and that he can observe whatever is immediately around the object being carried. The Code's prohibition against scrying applies when the user doesn't declare him or herself; otherwise, it is legitimate communication. They'll know where his focus is; the enemy shouldn't.
Vares can teleport others, not just himself, over modest distances (1000 feet or so). This could be enough to get party members in and out of areas. In other words, he can help alert others to what is going on and move backup or arrange an evac for those who don't have the teleport magic themselves. His spell is Mastered, and since we're in the Magic Realm the Aura doesn't contribute any botch dice, making the spell about as "safe" as it can get for now.
Separately, Vares has done a Horoscope for the region of the Arc of Fire where Khyrom's fortress is located. He can provide all of the Magi with copies to boost any Penetration to targets with which they have Arcane Connections.