Can't skip the phase anymore, it was patched a while ago.

You can use the holy method listed above or swap in a blm or 2 and use flare/firaga when needed. You can also try to leesh but normally you run out of time here.

The key to all of this is your war will only be able to SC 2 of the groups, thus stunning them to make it easier on the mages. That group he doesn't stun tends to beat on a few mages plus SE has some weird agro mechanics here when the mobs spawn.

Overall though it is not too bad and just keep at it.