The sentence that should have commas removed from its restrictive clause is:
An author, who you would like, is Helen Keller.
The clause "who you would like" is a non-restrictive clause in this case, which should not be set off with commas. It implies that the author being referred to is specifically Helen Keller, and the clause is essential to identifying her in the context. Hence, it should read: "An author who you would like is Helen Keller."