Spoiler
Explain Kodlak then.How is it he managed to get to Sovngarde? By your logic he shouldn't have and yet he is ( as long as you do the Companions quest line ). He was not killed in honorable combat, he was killed while in beast form and yet after cleansing his soul of Lycanthropy he will be in Sovngarde. Technically he died as a werewolf not a man so he shouldn't have gotten in by your logic.
But he believed his life and deeds done to be honorable enough to gain his place in Sovngarde, allowing him entry.
But he believed his life and deeds done to be honorable enough to gain his place in Sovngarde, allowing him entry.