Well my tuppence..
I think the line is reasonably clear..
1 and 2 are for the sake of things, TRAINING. At no point during your TR are the airlines making any real money out of you. There are no pax behind you, no revenue etc.
Although I went down route 1 and 2 (2 for my second airline - the 1st actually paid and bonded me!) I still felt bad about 2.
So with respect, I don't see how you can class 2 as PTF even though as said, I don't agree with it.
3...well that's blindingly obvious.
All the best.