I don't really get your point. If you backed the Fun Pack + the strategy guide on kickstarter / the backer portal that's basically the content of the so called Royal Edition on steam. I would assume that you get the missing content compared to the champion edition on the backer portal on thursday, so you don't need to buy an upgrade for the Royal Edition
Edit: I checked this on steam because I'm in the same situation (backed the Fun Pack + Guide). I redeemed the Champion Pack key on steam but when I try to upgrade to the Royal Edition I don't get a discout. Maybe the upgrade discount depends on your country or there's a difference between Kickstarter Champion keys and "normal" Champion keys?
