Footage:
90s-2000s Official Universal Promo videos
https://www.youtube.com/@ALifeintheParks
https://www.youtube.com/@CanobieCoaster
https://www.youtube.com/@Attractions360
https://www.youtube.com/@attractionsmagazine
https://www.youtube.com/@HawgGnarlyDude
https://www.youtube.com/@mgklmpg1365
https://www.youtube.com/@VideoTimeMachine/videos

Sources:

Islands of Fear: The Haunting Story of Universal's Failed Halloween Horror Nights Attempt » Epic Universal Blog
The Complete History of Universal Orlando's Halloween Horror Nights - Theme Park Tourist
2002 Cindy Concept - Expansions (2001-2005) - Horror Night Nightmares | Forums
30 Years of Fear - A History of Universal Orlando's Halloween Horror Nights: 2002 (The Caretaker Welcomes You to the Islands of Fear) - WDW News Today
http://www.solarius.com/dvp/wdw/attendance_figures