(iii) the use of a question mark to create the illusion that a clue has an andlit structure.
For the third in the series it seems that another apparent occupational hazard of the cruciverbalist is the gratuitous use of the eroteme, when none is justified. Consider this recent example from the EV series:
Far eastern region ? (4)
This is really no more an accurate definition of AREA for the addition of the question mark, which is indeed completely unnecessary to the wordplay. It seems this clue just needs a minor rewording to make it much more sound:
An andlit clue is one which reads in its entirety as a complete definition of the clueword and at the same time as a cryptic indication. It's essential that none of the clue's components, including punctuation, are otiose in either reading.
In some &lit clues, the wordplay is only part of the clue – this variant is called the semi-&lit, where in effect the wordplay enhances the definition, which should stand in its own right.
A well constructed &lit clue can indeed be a thing of beauty, but simply sticking a question mark at the end of a dodgy definition doesn't really do the genre any favours.