The rival has one of a sort. After a demo on Pokémon Smash! had the girl playing the game naming the rival "Hihihiroshi" as a joke, some fans thought it was the rival's official name. Even after the misunderstanding was cleared up, fans adopted the silly name until the official name, Hugh, arrived. Sadly, you can't name him this in the English translation due to Character Name Limits.
On Pixiv, Bianca with her new design has a tag that refers to her as "Berumegane."
A perusal of the game's music files would imply that the devteam had nicknamed Black Kyurem "Kyurom" and White Kyurem "Kyuram".
The Therian formes of Thundurus, Tornadus, and Landorus are referred to as Thundurus-T, Tornadus-T, and Landorus-T
Black Kyurem and White Kyurem are referred to as Kyurem-B and Kyurem-W, respectively. Kyurem-B is also occasionally referred to as "Kyube".
Jossed: The popular theory of the Strialton triplets secretly being the Shadow Triad is officially debunked here.
The Other Darrin: Oddly enough, no voice actors from the anime reprise their role in the animated trailer in either language. In the Japanese version, Bianca was voiced by Ayana Taketatsu instead of Shizuka Ito, while Elesa was voiced by Miyuki Sawashiro rather than Yumiko Kobayashi. As of the English dub, Eileen Stevens voiced Bianca instead of Erica Schroeder and Elesa was voiced by Sarah Natochenny instead of Eileen Stevens.