For many shots, your diagram is not correct from a visual standpoint.
For the edge-to-A or edge-to-C secondary aim line, you are correct, in an absolute sense, that they converge with the CTEL behind the CB (on the player's side of the CB). And when the CB and OB are close enough together that they seem to be about the same size, the two lines will, indeed, appear to converge behind the CB.
But if the CB and OB are far apart, the OB looks significantly smaller than the CB. In that case, the CTEL and the secondary aim line to A or C appear to converge in the distance (not at the player's eyes).
As to the edge-to-B secondary aim line, it is parallel to the CTEL in an absolute sense, i.e., they do not converge at all. But, again, if the CB and OB are far apart, they will appear to converge in the distance, not behind the CB.