Creator Backlash: Matsumoto has all but disowned Endless Odyssey. The first episode begins with a title card in Japanese (with no English subs, strangely) proclaiming the OVA series as being merely "director Rintaro's Captain Harlock". The fallout happened when Matsumoto took offense to a Star of David-shaped weapon Rintaro planned for the demonic villains to use.
Matsumoto also disliked the character Mayu (Tochiro's daughter) Rintaro created for Space Pirate Captain Harlock.
The Other Darrin: There appears to be two ships named Arcadia. One blue (seen in the 1978 series), and the other green, seen in all other subsequent series. None of the stories or animation supports the common fanon supposition that that the Arcadia was at any point destroyed and rebuilt. Or that the second Arcadia is just a newer, upgraded version of the first. Their existence actually nothing more than marketing.
cornponeflicks.org explains it this way:
Takara owned the rights to model kits from Space Pirate, and Bandai owned the model rights to Galaxy Express 999. When the Arcadia was slated to appear in the first 999 film while Space Pirate was still on the air, it would've amounted to free advertising for Takara; therefore Bandai had Studio Nue design an alternate version for them, to avoid giving their primary competition any leg up. (Studio Nue had also designed the blue Arcadia, and would shortly gain fame for its Macross design work.) In its own way, it's not far removed from having two different actors portray the same character in two different TV seasons or movies, in which cases viewers rarely have to contrive wild notions of secret plastic surgery in order to deal with it.
What Could Have Been: During a speech at an anime expo in 1995, director Noboru Ishiguro revealed that he was supposed to have made his debut in Space Battle Ship Yamato as the alter-ego of the brother of the main character. However, budget constraints forced the team to cut that part out alongside the 13 episodes where he would have appeared.