It looks like the two routes are mirroring the old Whitetail and NQPP routes. One allows training with any provider, but you can't apply until IR is complete. The other lets you apply before you start any training at all, but only with the four selected ATOs. Interestingly the second route refers to modular training, even though those ATOs don't seem to offer modular training any more (except Leading Edge perhaps).
One thing to beware of, it looks there are common 6 month timers across all of these routes, including the Speedbird Academy. That might mean that applying to one path blocks you from applying to another for 6 months, so choose wisely!