If Emily gets super she might raise to top contender, she had a lot of development dealing with her dad's bullshit so maybe now she is mentally stable enough to get powers, specially now that she is searching for Ella, who knows maybe whe she comes back she has a pill for Emily.
Most likely all the romantic interests will get their development arc.
Emily got hers, but seeing where the scenario is heading, I'd guess that the twins will get theirs after the events of the next updates, since they're directly implicated, according to good ol' daddy.
Demi took a backburner but theirs is somewhat started with the whole leaving the fanclub behind, dealing with the Clover mess and learning to control their power.
Alice could arguably be said to have had hers within the main story.
Same for Tiffanny.
Angie seems to be less of an important character, honestly. She seems more of a niche for a specific fetish, so I wouldn't hold my breath on the development arc.
Maybe the cutest amnesia nerd might join the ranks of the harem -I certainly wouldn't complain, I love the little yeller- but I have a feeling that might not happen. But with the multiple hints that she had some interest in the MC, or at least to be closer to him (which made Jake jealous btw), it's not totally impossible.
As for the others, either they are part of the main story, or... I forgot them. But I don't think I've forgotten anyone that isn't more clearly linked to the main story, aside from Brianna but I'm having the sad feelign she might fade away from the story entirely...
now i wonder what kind of power she will get like will it be a varity of the mc and ella power or will it be someting different like something to do with music or words like Uta from one piece where her songs created a whole different reality or would be more like how she sing a songs and the effect it different based on what kind of theme the song is going for like it could boost other superhuman powers, heal people, or just make them really sad and lonely and how strong could she become or rather how fast as Michael has said that she got the right instinct to make far in their world
I don't think she's gonna get powers. Ella stated that Emily had potential, but she was utterly incapable of figuring out which monster would be the best compatibility-wise. Just that her potential is even higher than the MC.
And having the wrong monster means either death or becoming a monster. Her being a fan favorite, and Ella being, for now, out of the picture, there's no shot at Emily gaining powers.
Plus Ella stated she didn't want to risk her friends lives.
And I feel like just making her get attacked for no reason out of nowhere would be way too weak, writing-wise. Especially comapred to the level WeirdWorld has shown so far.