Ragnor Lodbrok - a fun but not necessarily accurate ancestry

This week was the Season 2 finale of History Channel's The Vikings. An interesting take is http://www.academieduello.com/news-blog/facts-foibles-history-channels-series-vikings/  There is a descent through the Chellis family (my mother-in-law's maternal side) that has Ragnor Lodbrok as my boys 34th great grandfather through his son Sigurd Snogoje or Snake-in-the-Eye, as the show calls him. He is named this because his iris has the image of a snake encircling his pupil.

While Ragnor may be a composite of various Nordic rulers, Sigurd was a real person, along with the other sons, as told in Ragnarssona battr, The Tale of Ragnor's sons, After Ragnor's death, his sons took revenge but I don't want to give away any spoilers for the show. Ragnarssona þáttr informs that when his father died, he inherited Zealand, Scania, Halland, the Danish islands, and Viken. He married Blaeja, the daughter of king Ælla of Northumbria and they had the children Harthacanute and Aslaug, who was named after her grandmother Aslaug.

Could Viking blood explain the red hair on the Chellis side?

An 1857 painting by August Malmström depicting
King Aella's messenger before Ragnar Lodbrok's sons.