My first visit to EPCOT was Jan '83 when it had been open for just 3 months. Nothing existed where Living Seas is and Imagination had just opened up in full, not being quite ready at the official opening. The original Imagination 3D movie (pre EO) was very visual...floating thru an apple orchard in bloom, and the witch with electric fingernails

Everything was so new and impressive. Seeing Sapceship Earth for the first time as you approached on the highway was incredible. Kitchen Kaberet and World of Motion were top favorites. Miss those. I'm not sure if Horizons was open yet - I don't think so.
Innovontions was Communicore East and West and had some really cool stuff. Making dinner reservations at World Keys, located under Spaceship Earth and a few locations around World Showcase was really neat - touch screen play and video conferencing!
WS didn't have Norway or Morrocco. I did attend the Morrocco grand opening years later, with live camels and all!
25 years ago and during mid Jan slow season - we rode everything multiple times, soaked up every detail and ate at All the WS restaurants. Mostly as walkups and a few World key reservations.
Does anyone remember the name of he mascot that was on the touchscreen of the world keys?
I don't recall if there were any fireworks on the lagoon when they opened. During mid Jan they would have only been on a Saturday night if at all.
My girlfriend and I visited during our College senior year winter break. It was her first time to any Disney ever. She loved it too, so I knew she was a keeper - we married in '85.
We had a great, great time that first time. We always do each time we return.