I haven't seen much speculation on what Parson is going to do so save GK's units. I had my own theories, but a lot of them depended on whether Jillian would really press the attack to capture/croak Wanda.
Now we know that Wanda's group 'only' faces enemy archers (which they cannot retaliate against across city zones, I believe) and whatever fliers Jetstone's side has. Add to that Trammennis' bonus, Dittomancer and Healomancer support from the Tower and they could be formidable. They will have to fight while somehow avoiding enemy arrows. Wanda's team may survive but it is going to take some really bad aim, a good daily dose of luckamancy, some master-class foolamancy, and a solid plan by Parson to keep the key players alive. (good bye, Sylvia)
Charlie is still being surreptitious about his intent even though we all know what he wants: Schmuckers. I swear sometimes I think he was a Moneymancer before he found the Arkendish - not the Thinkamancer we assume him to be. Charlie wants his reputation in the West back, he wants his archons back, he wants the other Arkentools, he wants Parson and his bracer, and he wants to be paid to do it. We will see if the Gobwin Gambit comes into play here via a simultaneous surprise attack on GK by the Hobgobwin and Gobwin forces. (When it rains, it pours)
I believe that Jillian is now on her own agenda here - I'm fairly certain that Slately, Don King, and (possibly) Charlie all want Jillian to croak Wanda right now. I'm assuming Jillian is going to try her own version of Parson's "Capture the knight" and turn Ansom and then try and take him back to FAQ. I believe she will also try to take out the decrypted archons since that is probably a secondary goal of Charlie's as well.
If she is successful then GK should be able to make Ossomer their new Chief Warlord which should help Wanda's entourage's chances significantly.
Its been stated that Slately usually leaves battle decisions up to his Chief Warlord, but I think, in this case, he is going to override any decision of Trammenis' to attack Ansom and order Trammenis, the healomancer, and the dittomancer back into the tower so their bonus will help their inevitable assault on Wanda.
That would leave Haggar in the position of either showing their hand or helping out by going after the GK ground forces.
Assuming no more surprises here is my unimaginative defense-plan:
Have Ansom's crew destroy the bridge or otherwise create a bottleneck so that a smaller force can slow down/stop/whittle down a large one (ala '300').
Have Jack lay down some obscuring fog so no one outside of Jetstone's airspace can see in. That would mean they would be shooting blindly (which they could try) and would be forced to send in their fliers (also what air defenses does the tower have that can affect the airspace??) If Parson can get Chief Warlord status to Ossomer then that would help them trammen.. er.. tremendously against any incoming attacks.
but that is all tedious and boring

I'm sure they will have Parson create a new trick that will go down in Erfworld history like the Picard or Adama maneuver. Maybe Parson will find some way to take advantage of the 'time-is-relative' per hex/zone phenomenon and use it to juggle Chief Warlord status between Ansom and Ossomer.