Olaf the snowman from Frozen is rumored to have a meet and greet set up at Mickey's Very Merry Christmas Party. It is unknown if this will be an interactive meet and greet, but the assumption is that it would be.
November 7, 2014: The Very Merry Christmas Party debuted without an Olaf meet and greet. However, Olaf does appear in the Frozen Holiday Wish stage show.
September 7, 2014: WDWMagic.com user drew81 has reported that Olaf is rumored to have a meet and greet at this year's Mickey's Very Merry Christmas Party.