Can't trigger Lucanis' quest Inner Demons.
I use a Shadow Dragon elf inquisitor and I have saved Minrathous; after having done the different quests for Lucanis up to Bloodbath, I had the Zara's corpse whispering session, but the quest Inner D...
Forum Discussion
I think this is actually expected behaviour; if you let Treviso get blighted, then Lucanis doesn't do the introspection that leads to Inner Demons. He can still become a Hero of the Veilguard, it just happens later in the questlines.
Source: I played through once saving Minrathous and a second time saving Treviso. When saving Minrathous, I didn't get Inner Demons, but he did become a Hero.
