The attendants at Superman's funeral include: Hippolyta, Aquaman and Mera, Dr. Fate and Inza, Tim Drake, Barbara Gordon, Alfred Pennyworth, Lana Lang, Jonathan and Martha Kent, Kara Kent (Supergirl), Bibbo Bibbowski, Jimmy Olsen, Perry White, Orion, Lightray, and a few Green Lanterns (Larvox, Tomar Re, Katma Tui, Kilowog, Arisia, and Kyle Rayner).
Captain Marvel was initially considered as Superman's replacement, but the writers could not get the rights to use him so worked with Lobo.
The first time Metamorpho was referred to by name.
The only time in the DC Animated Universe that Metallo was voiced by someone other than Malcolm McDowell.
Dwayne McDuffie originally created the plot hoping to use it for a story-arc in Superman: The Animated Series (1996), but didn't get the chance.