ANSWER:

There are 2 types of the Prophet’s salla Allahu  alaihi wa sallam; ummatul dawah and this includes believers and disbelievers alike. 

The second type is the ummah of acceptance and response and this includes only those who answered him and responded to his call by following him, salla Allahu  alaihi wa sallam. 

Gog and Magog are from the 1st category.

Sheikh, I’m sorry to ask this again because the link you’ve sent from islamqa , i couldn’t find the answer for that. Is yajooj majooj amoung the ummah of rasoolullah? all of them are kafirs, bacuse of their fate is jahannam.many people confused of this.