Back to a four-horse race, the winner being whoever meets (not exceeds) the requirements at lowest life-cycle cost with acceptable risk.
That is, "whoever other than LockMart" for industrial-base reasons, and also because the T-50 is damn nearly the size of an F-16B.
The M346 is a nice solid airplane. It has an operational and maturing LVC capability built-in (from Elbit) which Raytheon appears to be throwing away in favor of a domestic solution. Industrial base? Yep, just what the customer's looking for, a new military airplane production organization.
NorthGrum doubtless has an interesting design, but the customer wants it to focus on LRSB (and other spookier things).
If you want a low-LCC new airplane, nobody does that like Saab. And Boeing's been working very, very hard on the ground-based bit of TX for a few years, grounded on very extensive experience in selling training systems to customers (for helos, particularly). And it's certainly the spread-the-work winner.
Boeing's deal to lose, I think.