Imam ARK's position on Ilm al-Ghayb
Alahazrat classifies the discourse on knowledge of the unseen into three tiers.
1. That whose denial constitutes disbelief;
2. That whose denial expels one from Ahl al-Sunnah, while not entailing kufr;
3. That whose denial does not even sever one from Sunnism.
Within the third category fall matters such as affirming that the Messenger of Allāh ﷺ knows the precise Hour of the Resurrection, that he possesses exhaustive knowledge of the five hidden realities without exception, that he knows mā kāna wa mā yakūn and beyond, the true reality of the soul, and the ultimate meanings of the mutashābihāt of the Qur'an.
Alahazrat maintains that the denial of the Prophet ﷺ possessing knowledge of these five matters does not expel a person from Sunnism - as far as I know al-Imām al-Barzanjī differed with Alahazrat on the question of the five hidden realities; but disagreement on such secondary theological particulars does not compromise one’s standing within Ahl al-Sunnah. Thus, we may differ with al-Imām al-Barzanjī on this issue while still holding him a proper Sunni.
In short, Alahazrat and al-Imām al-Barzanjī differed on the
amount / extent / scope of his ﷺ knowledge of the unseen, not whether he ﷺ
had knowledge of the unseen.