Hey, bro! Nice to see you back!
Anyway... my own answer...
Jasmine: Yes, undoubtedly. At the very least, in both the games and animé, she had the same sidequest, and the mangá, dumb as it may be, did imply something important (even if it implied something else as well...). In the games, she's got one of the most important sidequests, as it's the only way to even face the Gym Leader, and GAME FREAK managed to make it so the player could empathize with her, if only for the plot purpose. Sadly, the animé managed to do this one wrong by diminishing her role, changing her character, and adding a dumb and particularly UNneeded waste of paint/paper to the whole. (And not having the obligatory thing I like, of course.)
Pirika: The animé has this problem with making her be important, compared to the mangá (at least, it seems that due to how things went there, she could have had a better role), but Horohoro's 'Team The Ren' episode, as well as her bits in the first few episodes, are enough to make her important. And at least she wasn't an 'Anna mk. 2'.
Dawn: Very nicely so, overall. Of course, the animé makes her share a role with Ash, and the game version could have a much better personality, but... she's the protagonist. This, by itself, gives her a pretty good role in it.
Nichaela: She is part of the main team, overall, and is part of one of the story's romantical plots (if only it was with someone else... agh!). She also turns into the story's female lead by the middle to end of it, surprisingly.
That's it, for now... I hope someone else has a topic.