Predictability is meaningless. Ptolemy could predict the motions of the sun and planets in his geocentric model, after all.
You are wrong. Ptolemy could
approximate the motions of the sun and planets, but his model (unlike Heliocentrism) made errors that were detectable to the naked eye.
Ptolemy's model was, like all models, an approximation; but it was an rather crude approximation, which was the chief factor in it's demise.
The ancients could predict the motions of the planets with stunning accuracy.
Again you are wrong. The ancients did astonishingly well given the tools available to them, but they were unable to achieve the predictive accuracy of modern models (Heliocentrism, and RE)
How does a prediction of a sun passing by overhead once every twenty forum hours prove that the earth is a globe?
It doesn't, anymore than it proves that the Earth is flat. But . . .
by making the assumption that the Earth (along with the other celestial bodies) are globes in orbit about the sun, we find that we are able to explain their motions and positions with greater accuracy then in many cases can be measured. That is not the case with FE.
That is all science (Or Zeteticism) is. The fitting of models to observation. RE fit's astronomical observation. FE does not.
Despite your claims, FE has not provided a model whereby planetary motions and positions can be predicted. You have provided a model whereby an isolated observation may be accounted for, but you are unable to extract predictive power from this model.