User blog comment:Xilinoc/Ch. 542 - THE BLADE IS ME/@comment-10630156-20130620021814/@comment-11051098-20130620133608

It was stated in the main article about Yammy that he succumbed to his injuries and died, after the fight with Byakuya and Kenpachi. So it seems the only Espada that survived are Halibel and Grimmjow.

As for the gathering of the Stern Ritter, what seem to be all of them, it makes sense if Yhwach plans to attack Soul Society again soon. It would be logical to attack your enemy again before they can gather their forces and stand up against you.