@Stringer2048 Imp is good against single targets, especially with gravity grenade. Impkata is good for finishing off plants who have low HP. Overall, he is a good flanker.
Z-mech is a little difficult to keep alive, so the best thing to do is to deploy it as close to the plants as possible without letting them see you. If you do that, Z-mech can be good for flanking too and is pretty powerful at close range. If you find yourself surrounded, Explosive Escape will help a lot.