By the time of Baum's book, the popularized American vision of "Santa Claus" was less than a century old. The famous "Night Before Christmas" poem, having been written in 1823, defined the character as being a right jolly old elf and shaking like a bowl full of jelly and whatnot. Bits and pieces were tacked onto the Santa mythos in the decades following that poem, reaching its apex in popular culture with the legendary 1897 quote from a New York Sun editorial, "Yes, Virginia, there is a Santa Claus."
When Baum wrote his book, Santa Claus was still this disparate assortment of random facts. Nothing about the character was particularly set in stone, leaving Baum with a great deal of leeway in how he shaped Santa Claus and his world. Many of the truly insane things Baum created would end largely ignored as the Santa Claus myth solidified throughout the 20th Century, but his story is still a whole lotta fun. Also, in point of fact, Baum's iteration of Santa Claus is canon to Oz: he, as well as other creatures from the book, appear at the end of The Road To Oz, and his home is later shown on maps to be just south of Oz proper.
So, having said all that, buckle up, 'cause we're about to get HOLLY AND OR JOLLY.