Will the people of Paradise be called by their real names, or will their names be changed? And is the aforementioned Hadith about the two Books authentic, and why was the word "books" used in it? And did the Prophet keep written texts other than the Quran, even though he was illiterate?

It has been established through scriptural texts and a multitude of narrations that the Prophet, peace and blessings be upon him, was unlettered; he neither read nor wrote. Allah guaranteed to preserve the Qur'an and Sunnah in his heart, thus he had no need to write for himself. As for his command to write down the revelation, letters, and covenants, this was to document and preserve them for the Ummah. Regarding the narration about the two books that were in his hand, it has been said that they were merely symbolic representations for clarification. However, the more probable opinion is that they were real books containing the names of the people of Paradise and the people of Hell, but it does not necessitate that the Prophet read them or kept them. Rather, they were a revelation whose contents Allah informed him of.