The Northern leaders need to not be arguing over who owns what. They need to mount a united response now, with all the resources at their disposal, or they will be overrun in short order and making their first coordinated defense at the gates of Vizima or at the Pontar.
This means they need all their armies in the field, with the best war leaders in command, now and not after they settle their petty disputes. Their armies are not mere peasant levies or "lame drowners in colorful gambesons". They are veteran national armies who will fight with skill and discipline, who will fight to the death for the right commander. The Order, while not a national army, is a force of the same or better quality and can be counted on to ally with a united Northern front.
The Temerian army plays no small part in this. They are the best-positioned opposition between Nilfgaard and the Pontar. The core of the army, at least three thousand, is loyal to John Natalis; if Natalis commands them, they will fight, but otherwise they will many of them desert and disperse. Thus the strongest positions are those that preserve Natalis's command: either Anais goes to Radovid, and Temeria becomes, intact, a protectorate; or Anais goes to Natalis, and Temeria unites behind their girl-queen, if only united enough to fight for a while.
Where does Saskia fit in? She cannot count on the loyalty of the Aedirnian nobility or army, only her hayfoot-strawfoot militia and Iorveth's Scoia'tael. While they could defend a city, they would be useless in the open field. But that may be enough to hold a position in Upper Aedirn, especially if the nonhumans rally to her, and the Nilfgaardians refuse to be distracted into making war upon her.
It doesn't really matter in this context whether Saskia is freed of her spell or remains under control of the remnant of the Lodge. The mages need Saskia and an independent Upper Aedirn, and they're just practical enough to know it. Whether Saskia is a figurehead for the Lodge or a ruler in her own right, she's the best chance for keeping an independent state and place of refuge on the Pontar.
So I believe the "best" ending, in terms of being able to prepare for and resist a Nilfgaardian blitzkrieg that is surely coming, and coming fast, is:
Aryan LaVallette lives, so the LaVallettes remain loyal to Temeria. If the Baroness sells the LaVallettes out to Nilfgaard, it's a disaster. The Black Ones get a strategic position on the Pontar, Temeria is caught in the pincers, and Redania is invaded in short order.
I'd rather Loredo live long enough to make his deal with Kaedwen. As cruel as a Kaedweni garrison would be, it would be a professional army holding a strategic position. They'll hang Loredo as soon as he becomes expendable. Not possible on Roche's path, unfortunately.
Henselt lives, and Iorveth escapes the fall of Vergen. Henselt may be a skurwysynu, but he's the biggest, meanest skurwysynu the North has (and thanks to Geralt, he's got his mojo back).
Anais is delivered either to Radovid (and Radovid backs Natalis as war leader) or to Natalis (and the Temerian nobles back Natalis). This keeps Natalis in a strong position as war leader, and also Roche, the North's other leading skurwysynu, in the action.
Saskia lives; she, the remnant of the Lodge, and Iorveth will begin organizing a resistance movement in the upper Pontar. Henselt will have bigger problems to attend to than maintaining control of Lormark, giving them a fighting chance. Without a place of refuge for the nonhumans, Nilfgaardian propaganda will turn many of them against the North.