nicdanh
We have been to the parks a few times that same timeframe, but only stayed at the Poly in January(Hawaii LV). Let's start with the parks - each one does something special.....
1.the MK has a special night the park opens from 8pm-1am. (you must purchase a special ticket for this) At the park they will have a parade, Fireworks, cookies and hot chocolate, but best of all it will be snowing on Main street. Main street is pretty well decorated for Christmas.
2.MGM has a huge Christmas tree at the center of it's main street. Down below on the road that leads to the backlot it snow at night and they hand out hologram glasses and you will see snowflakes or angels around the lights.
3.Epcot has poinsetta plants that form trees as you walk in the main entrance. At the World Showcase certain countrys have storytelling of Christmas in their country.( I remember St. Nicholas at Germany).
The weather may get cold enough for a jacket and long pants at night, but during the day you may get away with shorts.
Walt'sFan.