And here is more evidence that the Vanir are very likely among the marauding rag tag band of warriors fighting the Asgardians and THor 2 (as horned helmet and on horseback warriors). This image is from Journey into Mystery Everything Burns book, Mighty Thor #18 prelude.
The man speaking is an Old Freyr, leader of the Vanir, in a flashback to the first Vanir - Aesir war. Their eyes are glowing because Freyr has made a shady deal with Surtur to give them the power to stand up to the Asgardians and a particularly nasty Odin.
Freyr: "Lord Surtur, did you mean what you said? Can you really inspire my brethren to stand up to the Aesir? To take what is ours before the Odinkind take it from us?"
Surtur: "Oh, my yes... for a price."