Aurvandil would be entirely useless in sending any sort of meaningful aide that far north. Even if they weren't in war with Madina I doubt they could spare even 1000 CS for the length of time it would require to reach the battle lines.
The Lurias are likewise too far to be useful and honestly I doubt we would need them.
Madina on the other hand may be able to send some help and, honestly, I think they would. After their whole "League of Free NAtions" speech it would be hypocritical of them not too.
On the other hand they could take the ultimate douchebag approach and not help us since we didnt help them, even though it would be an entirely different situation.
Even still, its a pretty unrealistic scenario. Our northern most Duke is a loyal Astroist and, unless he is the ultimate betrayer, a loyal Terran as well. In addition, our ruler is another prominent Astroist. There is no reason for Alana to declare war. Although of course, one can always come up or simply be manufactured...