It's not really all that big a deal as I'll probably never use it...but still, just in case:
Assuming Hall of Ancestors allows you to copy Shugenja Keyword onto an individual without it...let's say Akodo Shinichi.
Shinichi Attaches a Spell whose Cost specifically says "Bow this Spell" as a cost, with no mention of the/a Shugenja.
Does Shinichi need the Shugenja Keyword in order to use this spell as the Cost does not require a Shugenja and it is in play?
Note: I have received one answer, just wasn't wholly sure it sounded right so figured I'd see about an official ruling as finding the Rules on Spells seems to be harder than finding KD Boosters at a decent price.