User blog comment:Miskos3/Episode 273: Fairy Tail Zerø: Treasure, Review/@comment-7418318-20160227133616/@comment-7418318-20160228151503

I've listen to the line five or six times and I'm pretty sure it's hitori... but it matters little anyway, since even if he said futari, it could have far too many other meanings to conclude he can see Zera.

He could mean the two not present, Yuri and Precht as you said, since he saw the full team in town or it could mean Mavis and Warrod.

I think what's a bit more conclusive is something else:

SPOILER WARNING for anime only viewers!

Twice Geoffrey dispelled illusions while Zera was present, but he never dispelled her. If his dispelling needs to be targeted, rather than him dispelling everything within a certain radius, it would mean he can't see Zera.

Considering how the dispelling effect went only in one direction with the army and all around when he dispelled the burning town, it would make sense for this spell to need direction, rather than being all-around.

The reason why he ended up dispelling the buildings along with the fire and townspeople could be because all that was one connected illusion, so dispelling the flames and people also took the buildings down. While Zera is a seperate illusion.

Of course this is no guarantee, but it seems the most logical explanation to me how Zera wasn't affected by the dispelling.