Rion is the main protaganist and the Keytarist for the Flash dolls. She gets her powers from a hello kitty plush. Rion's mother is dead but she has a sister and a father.
Minamo is the violinist for the Flash dolls and one of the main supporting characters. She gets her powers from a cinnamoroll plush.
Kanna is the drummer for the Flash dolls and one of the main supporting characters. She gets her powers from a Badtz-maru plush. In the chinese manga, it is implied that she is a lesbian.
Ririka is the trumpet player for the Flash dolls and one of the main supporting characters in the chinese manga. At one point, she is a villain. She is Rion's sister and gets her powers from a mimi plush.
The Pocchaco twins are a pair of supporting characters in the chinese manga who were at one point villians. They get their powers from plushes of the little twin stars.
Van Khein seems to be the main villian of the chinese manga. It seems to have the ability to control magical girls using dolls and at one point is able to take control of Ririka.
Pauline is a minor villian in the chinese manga and one of the mind controlled magical girls. She plays the violin.
The mysterious girl is the nameless main villian of the second japanese manga. She has a cat companion that doesn't seem to be a pre-existing sanrio character. She seems to be able to mind control others as is shown in the second manga when she makes Kanna attack Rion.
This character is one of the mind controlled magical girls in the chinese manga.
On this poster from 2010 are three characters that don't appear in the manga. A my melody based girl, (on the far right next to Kanna) a small u*sa*ha*na based girl, (on the lower left next to rion) and a strawberry king based girl. (upper left next to minamo)
Guntan (?) Chan
Guntan-Chan is a character featured in a magazine with Rion that was sold at a convention by Azusa Rei. Nothing is known of her other than her existence in the doujin. In this tweet, Azusa rei says that the magazine was very short and each magazine was manually bounded by Azusa themself. This doujin remains unfound.