@BoneyM you said that the more moving parts added to a long term interrogation, the more complicated it would become but... As I see it, a Mindhole caster would be able to reset their interactions with each cast, so the increase in complication would be minimal?
If so, I would like to put forward spending the College favour needed to get someone with mindhole to be able to come in an re-check various questions asked in different ways.
Preferably someone who speaks dwarf and is good with languages.