Worth clarifying I think, this war is indeed part of the reason that the Elves were looking for help. The other half concerned Glorfindel’s plans in Angmar where he wants to finish the job he started over 1000 years ago. The Dwarves are key though. No people are better fighting in Goblin caves than Heavy Infantry Dwarves.
Despite Bofur’s sales pitch, the ground work for this war was laid out many months ago and Elladan and Elrohir have been on board with helping it since near the beginning. Indeed Elladan had traveled to Minas Tirith with Curunauth to speak to the Queen and King and arrange for coordination with them for the small forces of the North.
Elladan is acting as the Aragorn’s Captain in the North and there will be a good dozen Ranger Veterans. The men of Arnor are on a heightened watch for enemy activities. They just don’t know the exact reason.
Cirdan even sent a small group of Elves to help including an ancient Elven Mage nearly as old as Glorfindel, though she is only a little more skilled than Deor in magic. She is an Elf of the Light. Four warrior-mariners have already crossed over the pass to meet the Eastern forces and the Elven Mage joined a group that is scouting Angmar.
As to Kkósal, that has just begun.