Qualquer efeito que não tem nada escrito, pode ser ativado em encontros de combate, o que não pode é usar efeitos de encontros de combate em encontros que não são de combate.
  Então pode sim, usar qualquer efeito que adicione dado nesses encontros de cultista, sendo de combate ou não

QQ. When resolving a Spawn of Abhoth Special Encounter, can
an investigator benefit from a bonus that applies during a
Combat Encounter?

AA. No. A Spawn of Abhoth Special Encounter is not a Combat
Encounter. As such, bonuses that state “during a Combat
Encounter” do not apply to tests resolved during the Special
Encounter. (Note: This is in contradiction to an entry in the
Frequently Asked Questions section of some printings of the
Under the Pyramids expansion rulebook. This ruling takes
precedence over other rulings.)

maueze::QQ. When resolving a Spawn of Abhoth Special Encounter, can
an investigator benefit from a bonus that applies during a
Combat Encounter?

AA. No. A Spawn of Abhoth Special Encounter is not a Combat
Encounter. As such, bonuses that state “during a Combat
Encounter” do not apply to tests resolved during the Special
Encounter. (Note: This is in contradiction to an entry in the
Frequently Asked Questions section of some printings of the
Under the Pyramids expansion rulebook. This ruling takes
precedence over other rulings.)

maueze::QQ. When resolving a Spawn of Abhoth Special Encounter, can
an investigator benefit from a bonus that applies during a
Combat Encounter?

AA. No. A Spawn of Abhoth Special Encounter is not a Combat
Encounter. As such, bonuses that state “during a Combat
Encounter” do not apply to tests resolved during the Special
Encounter. (Note: This is in contradiction to an entry in the
Frequently Asked Questions section of some printings of the
Under the Pyramids expansion rulebook. This ruling takes
precedence over other rulings.)