Circle Throw will fail to end wild Pokémon battles or switch out the opposing Trainer's Pokémon if it has the Ability Suction Cups, is under the effects of Ingrain, or has Substitute set up. In a Trainer battle, it will also fail to switch out the opposing Pokémon if there isn't another to take its place.
Same for Dragon Tail; neither of them will force the Pokemon out if they break the substitute. Roar and Whirlwind will force the Pokemon out if they are behind a substitute.
Circle Throw
Dragon Tail
No, if your opponent's Sub is broken by Dragont Tail/Circle Throw they will not be switched out.
