ossian666 wrote:
The prob is that it says it explodes and everything inside is then vaporized...
Actually, the adventure reads "If forced open, the crux crumbles to ashes and any objects it contains appear on the ground at the site of the fiery burst."
The objects inside are subject to the fiery blast, but not automatically destroyed. You can assume that the head would likely survive, as well as the silver box and maybe even the wands. The portfolio and the scrolls are almost definitely destroyed.
Between the information that Ailyn has and the experiences of Khazrae, as well as some decent information gathering, it's possible that the party could piece together some of the information about the lost Pathfinders. They should, at least, be able to track down Ghaelfin and Coriana... which is a decent start.