Here's how I remember it:
Early Entry (I believe it was called "Surprise Mornings") existed for resort guests for many years from the early 90s through October 2001 when Disney cancelled the benefit due to the 9/11 tourism halt. It was replaced with the lackluster Character Caravan where Disney characters were available for a meet n greet at the bus station at each resorts on most (not all) days. They were only there for a couple hours each day too.
In 2003, Disney revitalized the Surprise Mornings benefit as Extra Magic Hour. It was only the morning though. Then in 2005, Disney introduced evening Extra Magic Hours.