But, Lord of Fire, you're forgetting that Tyranids cannot be screened, due to the "Shoot the Big Ones" rule.
BTW, I believe out of those given, a Hive Tyrant with wings, two sets of scything talons, bio-plamsa, toxin sacs, two sets of adrenal glandsn and extended carapace is nothing short of nasty.
Happy Trails.