Swap with a different anonymous space, try again with five more pomegranate seeds, juice them first, same orders.
"Thank you." Invisibility, of course. He casts around for a power that would let him detect invisible people, and gets a density manipulation ability that highlights where an object is more or less dense than its surroundings. He doesn't need the teleportation; this telekinesis can do double duty now that it's at full power. He blasts out from underground, setting the fairy down beside the hole. He starts attacking invisible fliers first.
At least sorcerers' magic isn't going to be definitely useless later. His second objective can still be a success. He switches to trying to force-feed them crushed fruit seeds.
Preventing them is trickier now that he has to actually move. He dodges those he can, and increases his and his costume's mass to make himself more resistant to temperature changes and crushing and various et ceteras. Whenever he gets a sorcerer identified and incapacitated, he crushes a seed against their teeth and pushes the liquid back.
In cases where he has time, Eidolon also tells his vassals to heal those who are already deaf and not interfere with him capturing the rest.
Telekinesis lashes at the escaping subset, pulling them downward. The extremely non-invisible green figure flies toward them and tries to capture the dozen-odd escapees.
"Don't go deaf, stop fleeing."
In retrospect that does make sense. They quickly find themselves heavy enough that their wings can't carry them. Rather than try to heal them himself, he calls to some new vassals, "If you can heal invisible deaf people, come here now! Cure these ones!"
"Who are you, why were you the only ones running? Answer honestly."
The fairies with blood on their lips recite their nicknames (Plural, Mirage, Applause, Imagine, Yaw, Syrup, Luck, Trance, and Guess). And then, more or less on top of each other, reply variants on "Master told me to", "Peak told me to", "Favorite told me to", and "we weren't running, we were flying".
"Who is master of the most vassals here?" There's probably a single figure at the top, but it's not inconceivable that there are more.
It's probably one of the ones whose mouth nobody could repair, since apparently the harm is a necessary component. The flaps of skin that aren't supposed to be there become lighter until they essentially evaporate, as painlessly as Eidolon thinks he can manage. "Heal them," he tells one of the sorcerers who successfully healed the last set.
"Stop doing the mouth thing. It won't help anything." To the sorcerers, "heal them whenever they're injured." He unseals the holdouts' mouths.
"Which of you is Peak?"
"Are all the fairies here your vassals, and is anyone your master? Other than me." He unfuses their teeth, vaporizing a thin layer of enamel.