Wrong.
Lava Plume cannot kill Zac-c within 3 turns, so it dies to ImpriTrans Zacian-C. I think the best counter of Zac-c now are FC Zama or FC Gira, cuz FC Giratina can tolerate at least two times of all moves, and also immune to trapping, so it can deal with ImpriTrans, but it need to make sure...