Is Santa Claus a religious figure?
No. Business-version Santa Claus is not religious figure. Coca-cola and Haddon Sundblom caricaturized historic St. Nicholas for advertisement and sales purposes in December. There is no religious interest in it.
Yes. Historic Santa Claus was St. Nicholas, bishop of Myra, Turkey, a leader of Christ followers in 4 AD century.
An answer depends on which Santa Claus in question. See “Chronology of St. Claus: from history to art to business”