Vikingar is an odd one. I've always counted it as a coaster and it was listed as a coaster on rcdb at one point, which is why they have so many pictures of it on there.
I'm not convinced rcdb are being 100% consistent with their categorisation with this one either - I wouldn't say it was any less of a coaster than Atlantica at EP. Strangely, they don't even count all the Mack supersplash rides anymore - the one at Plopsaland was taken off the database at the same time as Vikingar. I don't see why that doesn't count if the Atlantica clones do.