The Third Issue:

Takdhīb/denial is a matter of the heart; its essence lies in outwardly denying something while inwardly believing it to be false. Ibn Al-Qayyim, may Allāh have mercy on him, said: «فأما كفر التكذيب؛ فهو اعتقاد كذب الرسل» "As for the disbelief of denial, it is to believe that the Messengers are lying." [Madārij As-Sālikīn (1/346)]. I say: since this is a matter related to the heart, it can only be recognised when a person explicitly reveals what is in their heart (refer to the discussion on "Istiḥlāl" : pp. #, #, #).