If any house has Speak With Dead it is likely to be House Tachonis. That is a problem with Hannan dead. The one saving grace is that he is under no obligation to reply when he recognizes the caster as an enemy so that would rule out anybody he recognizes as a Tachonis. Primus would probably have to get a Tachonis that knows it who Hananna didn't see right before (and also get them to dress not goth lol)
It kind of seems like they are planning on bringing him north with him being covered next to the cart but if not, the Schemers might be able to get him. Maybe Wick can get an invite from Petra and Ryah.
Anyways, the party might be fine. Primus will probably figure that his order sent him and not the party so his questions could be geared torwards that.
His three questions could be.
Q: How did you know Mara was here?
A: An armored human man told me (Hannan doesn't know who Azune is)
Q: What is the most in-depth description of him that you can give?
A: [A description that uniquely fits Azune and obviously fits an Arcane Marshal]
A: Vaelus of the Mournvale (Primus doesn't know who that is) and a pixie.