Mostly correct, but they did in fact sacrifice slaves to accompany powerful men to Valhalla.  That was recorded by an Arabian trader who lived in real life and then got to be in a movie called 13th Warrior.

Sigurd!  He's the youngest and his birth was foretold.  To prove that he is a descendent of Odin, he will have the mark of the serpent in his eye.

Yeah, they did that to Aelle in fact.

If you read the Ragnar Sagas (which for all I know you might have) pit of snakes isn't the most sharks with frickin lazers type thing by far.  I'm sort of glad they cut out the part where he fights a giant snake dragon, or that his first son has no bones in his legs.

The Vikings storyline seems to be running on the presumption that Siggy is drop-dead gorgeous.  Which, while she is an excellent actress, is not quite true.

I really like how you're name is Aethelred.  I know this is unrelated, and you may know this already, but in real Viking times there was an English king called Aethelred the Unready.  Take a guess at what he was unready for.

Boas with a venom more powerful than the most powerful snake venom on earth to kill Wigea that fast.