Since they mentioned they also hinted they had Exia's GN drive I would wager that he came back alive. Allelujah I'm not so sure about, but we don't know who Marie was yet so he might have managed to survive somehow too.
I remember saying Patrick and I guess I was right. When his suit was hit only the upper half was destroyed. The cockpit of the GN-X sits fairly low on the chest and it was clearly intact when we see the remains float away.
Someone had to be piloting the new Original GN Drive bearing Gundam Saji saw and I suspect it would have been one of the original pilots (Setsuna or Allelujah), or possibly Felt.
The Tieria look alike is also a Shirin look alike and the laugh sounded like her so hopefully he'll stay dead and we won't have to choke down a Tieria clone factory plot line.
the biggest mystery though is will OO Gundam be better than the Wing 0 it is doomed to be a clone of? Or might it actually surpass the godhood that is Strike Freedom.