Mungo Man,
A bit of a long sad litany your list.
Whether he was paying or not, he certainly shouldn't have been landing in KOS, and he shouldn't have been sitting in the RHS without a safety pilot.
Had the LTC been incapacitated there was a 9 in 28 chance he would have stoved it in on landing, which he managed still WITH the benefit of a conscious LTC
It strikes me that this guy was not only a bit marginal on ability, but as you say, not even current enough in terms of recent hours to fly a Cessna 150 never mind an A320 on a revenue flight.
He should never have been sitting there with his hands on the controls landing where they were, with no safety pilot ,with his lack of recent flying experience, and his training record.
Not so much to do with pay as you go schemes, but everything to do with the training Dept of TC at that time not knowing who/what the hell they were using as an unsupervised F/O ( Capt if the real one pegged it
)