Is it permissible to say that human knowledge is created by God? And is it permissible to say that God may reveal the unseen to some people other than prophets and messengers, such as Ibn Taymiyyah's vision concerning the Tatars?

Allah's knowledge of His creation is an attribute of action pertaining to Allah that is not described as created. As for human knowledge, it is among the acts of the servants that Allah has created. The awareness of some of Allah's servants of relative unseen matters is possible through divine unveilings (mukashafat) and inspirations (ilhamat), as happened to Umar ibn al-Khattab and the inspired narrators (muhaddathun), and through truthful dreams (ru'ya sadiqah) that foretell the future. Such an event also occurred to Shaykh al-Islam Ibn Taymiyyah, where he predicted the defeat of the Tatars, and this might have been based on good anticipation of Allah and His promise of victory, and not necessarily on inspiration or a dream. A distinction must be made between divine inspirations that occur to those who are steadfast upon Allah's law and the satanic suggestions that occur to the allies of Satan.