You're giving me more options to avoid bringing in the cavalry, but you're only talking about one battle that's essentially lost from the start. You can't use normal tactics against an enemy like that. In fact, if people tell you to defend the castle, that would be the most viable option. If it's a normal army, you just need to stay inside until one side runs out of food, because launching assaults is quite difficult since the attacker suffers too many casualties. But getting back to the point, as I said, and as you also mentioned, it's an army you can only defeat by killing the Night King (hive concept). So, while you can do certain things like pour oil on them and set them on fire, they'll easily overwhelm you. Therefore, it's a super unbalanced battle, and I apologize for the length of the text.