One thing I also found interesting that might be a minor detail but I found it interesting at how Queen Beryl's throne room was depicted in said scene. It is a far cry from how it was depicted in either the 90s anime, manga or Crystal with a large almost seashell like throne with the purplish background, the almost coral orange throne and purple floor. It honestly looked like it could have been a good throne room or villain base for maybe an aquatic themed set of villains under the sea or atleast to me.
Good catch! I hadn't even noticed that until you pointed it out. Since aquamarine is a variety of beryl, perhaps the seashell throne was an intentional allusion to that? (Honestly, given that this series is called Sailor Moon, I'm surprised we never got an aquatic-themed set of villains, unless you count the ones from the Kaguya Island musicals.)
The first season books are kinda weird because they randomly introduce villains, and don't disclose whatever happens to them. If I remember correctly, Jadeite and Nephrite don't really die. They just are never heard from again.
They got better with this with the later seasons, though Tellu, Viluy, Cyprine, and Ptilol are all excluded from S.
The picture books are incredibly colorful and cute IMO, but there was clearly no editorial oversight. The episodes they decided to adapt were so random, they leave a bunch of dangling plot threads, and they skip over so many characters and plot points that I think most fans love / would consider iconic. A very strange piece of the franchise, but that's why I'm super into it