That's another good idea, thanks! The dead NPC was a conjuration wizard (and the party's only arcane caster), so they went with getting him Reincarnated. With the PC paladin, the party's tolerance for Laori Vaus is pretty much zero anyway.
In fact, there may be a similar issue with even listening to Count Sial unless I make some tweaks there... maybe he should be a NE cleric of Nethys instead of Zon-Kuthon.
I agree with your take on Book Four and the likelihood of the players getting bored with all the reputation-building challenges, i.e., "faction reputation grinding" to use an MMO term. I'm considering options to trim that part down and streamline it, basically give them fewer hoops to jump through and hopefully link in some more PC-relevant* challenges.
*Gnome cleric/crafter of Brigh
*Half-orc paladin of Sarenrae
*NPC human wizard (Conj)