(d) 18,000hrs and excellent crew resource management skills.
Realistically, by the time somebody gets to, say, 5,000+ hours it's completely irrelevant how they initially trained - it's all about the experience in the second half of their flying career. The concerns that many people have in the MPL is for the first officer and their ability to handle emergencies in the early part of their flying career.
For example if
this accident were to repeat with a new co-pilot on board, I'd be much more confident in a first officer with 1000hrs of flying instruction and air taxi flying who had just got their first airline job, than one with 200hrs on an MPL course and had also just been hired the previous month.
G