but there is an important distinction to make - a company that owns the rights to this media may produce official additional media that may not canon because the author of the original work didn't have any contribution or say in it, but it is still official because it is produced by ...
I've heard about him/it = I've heard of him/it ("heard about" someone is less used for people unless you mean to imply something happened to him. "Have you heard about Lily? No, what happened?") I know about it I know of it ('Know of' can sound a bit formal but it's gen...