The only part of FET which seems to be "zetetic" is that the ground appears flat in your own small viewing area.
Everything else (The UA, antimoon, sub-moon, bendy light, bioluminescent sun and moon, the ice wall, the conspiracy even though they state that it isn't actually part of the theory, harmful moonlight, the earth magically not producing a gravitational field, electrostatic repulsion keeping the stars planets and sun aloft, any map they can come up with, etc.) are theories with not even observational evidence to back them up, therefore are anti-zetetic. To make any of these predictions, you must first assume that the earth is flat, and that the RE explanations are wrong, which zeteticism forbids.