Pokegirl wise, Lillies my absolute favorite return, followed by Serena (yes I said it) and Iris tying for second, Iris being next and then Dawn.
Lillies the only Pokegirl and character who managed to complete the goals she set for herself and her families well deserved conclusion to their Mohn search arc was absolutely beautiful and an incredible milestone. I haven’t watched the Alola battle royale episode yet, so I won’t comment on that, but Lillies really come a long long way since her SM days and am looking forward to what the future may have in store for her next.
Serena isn’t my favorite Pokegirl and I don’t care for her too much, but giving credit where credits due, her glow up in JN is a major improvement from how things with her ended in XY. She played an important role in mentoring Chloe and helping her shape her future. She’s matured a great deal in her contest progress and I wish her a lot of luck. Iris’s glow up is just as much great to see too, finally becoming a region champion and taking that big step towards her dragon master goal. Becoming essentially Ash’s strongest traveling companion has made her grow a lot since BW and I’m really proud of her.
While Dawn didn’t get much change since her last reappearance in the series, I also don’t share the same sentiment that JN “ruined” her like some here like to exaggerate on. Her coming back so much and interacting with the cast again, also being the first to help inspire Chloe, has been great to see. Dawns always been a fan favorite and doesn’t need too much updates or change in order to make me happy to see her. So while her reappearance in JN wasn’t as strong as others, it was just as exciting and great to see her as we did the others.
Disregarding the Pokegirls, Gary is easily the strongest return from the male characters for me too, followed by Kukui and Brock. I thought we’d never see him again since his days in Sinnoh but to come back as the rival for Ash’s new companion and help encourage and teach him a few things has been amazing.
Kukui doesn’t have much on his plate (SADLY!) for his returns in JN but it’s an amazing milestone to see him having developed a family and bring forth a little brother for Ash to have. Gary’s the stronger return but Kukuis the one I like more.
Then we have Brock, who’s great to see again since SM, and is getting closer to his Pokémon doctor goal.