Although we often speak of the (1)sensations, (2)feelings, and (3)anticipations
That comes from Laertius' summary:
D.L 10.31 In The Canon, Epicurus affirms the criteria of truth are the sensations and the preconceptions and the feelings, and the Epicureans (also affirm) the image-based focus of the mind.
We also must remember:
We have Epicurus' words on the issue. Epicurus tells us exactly what the anticipations are in PD 24:
PD 24. If you simply reject any one sensation and you will not separate (A)a theory about what is still pending versus (B)what is actually present according to (1)sensation, (2)feelings, and (3)the whole visual focus of the mind: then you will disturb even the remaining senses with empty thought – as you will be rejecting the whole basis of judgment.