So I kind of poo-poo'd on this idea when the Masque bonuses were first revealed, but with additional info it seems they can be of great help even without the Silent Shroud bonus.
Shadowseers get a spell that deals D3 mortal wounds and -1 to leadership. Units suffering casualties from Death Jesters suffer -2Ld and you choose the first model that flees.
You could do an easy investment of Silent Shroud Shadowseer + 2-3 Death Jesters and a Solitaire. Inexpensive, enough characters to spread around their roll 2 dice for morale aura, and you unlock their stratagem that lets them ignore overwatch, which is very useful for Coven units.
Seems good. You can also even make the Shadowseer a warlord for a trait almost as good as LabCunning.
You could do:
Either should be pretty fun.