FYI: Mew EX with Genome Hacking already exists in the Pokemon TCG Live app and we know how it works.

In TCG Live, if you use genome hacking against a mon that has a move that discards energy at the end, you in fact do not have to have the required energy to discard. The move works and the energy discard does not happen.

Given that that is also an official TPC mobile app, it seems very very unlikely they will make it work differently in this game. So unless something very unexpected happens, we can rest fairly assured that this move will work to kill Charizard.