The Foundation never bothered with the Encyclopedia Galactica, Empire is told. In Asimov's books, it continued as a minor function. It is often used for scene setting: a reliable source that may not know the full truth.
Cleon the First knows about Earth, and presumably that it was humanity's original world. In the books, this knowledge has been lost by the time of Hari Seldon. It is one of several candidates for the honour.
Throughout the series, there has been mention of Robot War, in which all robots were supposedly destroyed. This differs from the books. Originally the Robot and Galactic Empire series were separate. When he returned to the Foundation stories with 'Foundation's Edge', he made a link. It is later explained that a majority of the robots decided that their visible presence was bad for humans, and they withdrew. Their continued existence is kept secret.