Skippers and biomissiles were destructible in WC3. I don't recall shooting regualr capship missiles down, but they might have been. Torpedoes also could have been destructible, just not by laser turrets.
Ah, and one note about biomissiles. Destorying them was fairly easy, and Hobbes (or most likely any other wingman, I flew it with Hobbes) did quite well killing the destroyer that launcher them. So I don't see why does WCS act as if the Locanda attack was sucessfull. On my playthought, it wasn't. When my father played WC3, he also stopped it. So I don't see why WCS assumes that I failed this mission.