Justice is Served
Bringing justice to Cosutanu in this situation is difficult.
Daciana Mitriu has commited a horrible crime against the population and specifically against the Nectrias. But that crime was only enabled by a previous crime, commited by Valor Radulesc two centuries previously. And that crime was only committed as revenge for another crime committed against the Radulescs by the ancestors of the current Nectrias. And arguably even that crime was committed in response to another alleged crime committed by Gorgu Radulesc against Severu Nectria - though in this case, the details seem lost to history.
In the words of the Ayodeshi Jurist, Modi Gu-Mamat:
"How might justice prevail When injustice becomes the snake That eats its own tail?"
Daciana Mitriu
If the players manage to piece together enough evidence, they may realize that it was the actions of Daciana Mitriu that led directly and intentionally to the death of Gavriela Nectria and to the outbreak of Black Rot in the village.
If the evidence they can present is convincing enough, Daciana Mitriu, and anyone else who was privy to what she did (Crisandra Lotti and Captain Bucur), will be in very serious trouble. Daciana could potentially receive a death sentence, and as the Matriarch and head of her family, their assets, lands, holdings and other entitlements could be broken up and seized to make reparations to their victims. Obviously, Daciana will stop at nothing to cover this up, and would even go as far as to hire assassins to eliminate the party if necessary.
Historical Justice
If the current head of the Nectria family (Pawel) accepts responsibility for his ancestors having murdered the Radulesc family and offers to abide by terms of reparation to be decided by the Council of Cosutanu, the ghost of Gheorigu Radulesc may be put to rest.
This will be a complex process, as the actions of Valor Radulesc, and his appeal to Mol-Imit are an inexcusable crime, and he must remain ‘Denuntatiu E Blespematiu’ forever. Allowing for that, the risen Radulesc family (except for Gheorigu himself) would need to be defeated, then ritually embalmed and properly re-interred in their tombs with all of their burial treasures, while Valors body would need to be removed from the tomb and destroyed. The entire tomb would need to be re-sanctified and then sealed.
Additionally, significant monetary reparations would need to be made, but with no Radulescs to make payment to, these reparations would probably need to be made as some form of grand public work, such as the construction of a Cathedral or other edifice built in the Radulesc family name and paid for by the Nectrias.
Certainly if the player characters find a way to hold Daciana Mitriu accountable for her actions there is a much clearer path toward justice. If Daciana is convicted of her crimes, and the Mitriu family assets are broken up to pay reparations to those harmed, the Nectrias might be convinced that their 'share' would be best invested in their own absolution.
In any case, the path of bringing justice to the Radulesc family is the most complex and difficult by far.