I don't think there is anything wrong with Surf and Waterfall's categories.
Waterfall the Pokemon is physically climbing the waterfall or physically hitting the opponent in an upward motion while Surf, they summon a tidal wave.
Spark on the other hand, I haven't seen any anime version, but from the visual effects I don't see how its Physical.
Spark is a physical move because in the move description, it states that the move is an electrified tackle, hence making it physical; however, in the anime it was somewhat inconsistent on how it was portrayed (in the Johto saga, it was portrayed in a similar way to Thundershock and Thunderbolt, but in the Hoenn saga onwards, it became portrayed in the same way as in the games).
Razor Leaf is physical because it involves launching leaves at the target. Moves that involve throwing items (like Rock Blast, Bullet Seed and Barrage) are physical as well. I think Magical Leaf remained a Special move in the physical/special split because the leaves launched have special properties that enable them to almost always hit the target.