Re Norwegian:
I personally know 3 that will start there. Two of them have no commercial operating experience but some FAA flight instructor experience (don't know total time, guess 1000-1500 hours?), but have worked in the cabin for a while. Third one is quite experienced smaller single- and multi turboprops and has worked with handling for DY before.
I've also heard that one other guy where I work is starting with DY, I don't know his experience level. Rumour also has it that there's quite a lot of the laid off SAS guys starting, although I would not be able to confirm that.
So it seems there are two ways in; a ****load of 737 time, or a foot on the inside.