Мафия 86. Vallée des Roses

Marcus, at least, has one defense.

Exactly! I didn't notice. Then it's not Morny, because Marcus kills everyone first, and he wouldn't have had any defense to lose. So, Morny really is Kirsa, most likely.
And who do you think could have attacked Blagovest? I think it's most likely Marcus; a marksman wouldn't kill someone randomly.

Added 1 minute ago

Countess Melissa de la Luna - Her people do not know their home and wander the world like strays. -
could they have thrown such a countess into a grave like a peasant, like a stray?

No. Melissa's ND (Note of Death) comes after the wizard's murder, and it was recorded.

Added 1 minute ago
Mona, the treasurer resurrected Ruddy. Because the description in the newspaper about Melissa is much more like recruitment than resurrection as a zombie...