Hey when did Mat die twice?  He thinks he is no longer bound to the horn because of when he was hanged but the heros imply it was from another death that Rand saved him from.

The assault on Caemlyn in tFoH. Rand balefires Rahvin and brings Aviendha, Asmodean and Mat back.

Am I the only one who wondered where Shadar Haran was? he was meant to be this uber fade yet played no part(Im pretty sure I didnt see him.)

He's shown as an empty husk on the floor. That's it.

I think the most likely explanation is that Ishamael's probation periods fall under the domain of RJ handwaving it. Early on it seemed RJ was still deciding on metaphor versus metaphysics and so he threw a little bit of both in there.

Also, Aginor and Balthamel aged as they did because they were "trapped closer to the surface" and are consequently the first to be released when the seals weakened enough.

Did Birgitte spend any of her previous incarnations in Seanchan? Mat having his memories transplanted from visitors to the Tower Of Genji would explain why it's all from this side of the Aryth Ocean. But in Birgitte's case it would seem that souls are recycled on a per-continent basis, which is kind of... odd.