Last year it was Saturday & Wednesday nights in the beginning of December. Saturday at 7:00 & 9:00 (fireworks 8:00, park close 10:00), Wednesday 6:00 (fireworks & park close 7:00). Fireworks other nights at 6:00 (park close before
MVMCP). Word of warning - MK will be more crowded on Saturday & Wednesday during the day since those are parade nights.
The last storyteller shows in the World Showcase are around 6:00 to 7:30. Each countries version of Santa explains their tradition. They might be too young for the Candlelight Processional.
You could take a tour of the deluxe resorts to look at their decorations. I remember seeing a show in the Yacht Club where Santa explained the legend of the bell and each child got a small bell on a red ribbon.