NPPL
As with most aircraft (apart from helicopters, to which I am accustomed) differences training is required not a type rating, apart from the Malibu.
The NPPL allows you to fly the basic aircraft on a HGV medical. Less dual instruction time is required, but realistically who can pass as a competent pilot at 40hours TT? If it seems you're going to fall under the 45 hours for PPL, add a night rating to it, fly other aicraft, build solo time - so you're not wasting time.
If your final goal is the airlines, then there is no point getting the NPPL as you will have to upgrade it to a PPL anyway.