Cassie's Roll'n'Shoot combo givers her shot 195 bonus damage a shot if she can consistently hit you. and it reduces her roll's cooldown to 1s. If she rolls, try using a movement ability to make her miss out on the extra damage have to wait full time.
Ying is limited to 2 stationary Illusions. If Ying wants to push up she needs to sacrifice illusions to make new ones to heal or her team will need to fall back for healing. Killing her or her Illusions gives no healing for the enemies to retreat to.
Ying's Ultimate ability, Illusory Rift, heals but can let her use her Dimensional Link to teleport to her team. If Ying uses this right after respawning, look out for her teleporting to her team and kill her to waste the Ultimate.