Talus is a good champion to flank Dredge. Talus can disrupt Dredges flow of dealing damage and stop him from spamming his AoE (Area of Effect) attacks. Talus should kill him if he can but teleporting back to his portal is still ok as you dealt damage
Dimensional Link can also let her travel to the last active illusion spot after it dies, and this can help her escape combat quickly, especially if she has an illusion hidden to heal her team. She is only able to have 2 active, so know their spots!
Watch out for his ability to leave behind an explosive fissure, and stay away from it! This would result in him getting healed and you taking severe damage. Make sure to track him too, so as soon as he is physical you can attack and kill him.