if its a high points game (or you know your facing abbodon) tyrant guard are awesome as u hit them with catalyst. flying hive tyrants rock and scare the hell out o your opponents so remember he'll be the first to be shot at so its a good idea to give him warp field. As for the one with the gun u can never go wrong with a venom cannon. twin linked dev's are nice but at 18" range generally means he may have to expose himself and while tyrant gaurd are nice they dont protect from blast weapons
Lash whips is the way to go