Next!! @kat. Starting with Ethan–top down…
Okay, I have two things under personality, and they're both major. One: you mention his major flaw as pride, which is fine, but then his personality type is described as laid-back. This is WAY too big of a difference–he can't be type A and type B!! Contradictions are okay, but this one is too much. Two: no prejudices?? None?? Listen, I understand that he might be an accepting person. However, everyone has prejudices, no matter how hard we try to hide them. :3
Aww he actually has a happy backstory!! This is rare, but I like it. The only major thing I have to say is that you should probably go into a touch more after-the-fact detail. Your second paragraph sets the stage, but I'd like to see more about him and Halcyon. Other than that, I think you have a nice backstory here. One you get some prejudices, though, you want to put those in here.
I'll overall at the end, so–Luke!! Top down…
Okay, personality page. I like him as a person, but I can't understand how he's a villain! He seems like an awesome rebel who just wants to have a good time. That's great, seriously, I love characters like that!! But it doesn't explain why he would be villainous. I would recommend tweaking the motivations a bit to accommodate this. See, if he's only here for a good time, then it doesn't make sense that he would (I'm kind of guessing here, so presumably) stand his ground and keep fighting the MCs. But to nit-pick: you call him cool and collected, but the entirety of his personality describes someone restless, reckless, and wild. This kind of doesn't make sense. Also, under mannerisms, I would recommend some physical tics–you know, stuff like 'plays with hair when nervous,' 'taps foot when stressed,' etc. Again, the prejudices!! Everyone has them, I'm telling you.
Backstory works for him, and I like it, but it's the same issue–he doesn't seem like a villain! I don't love to hate him right now, I love to love him. Villains can absolutely have happy backstories, but I really think that you need to go into more detail explaining how he actually became evil.
Finally, Kellan!! Top down…
Personality is AWESOME! Very, very nice job. There's only one thing I have for her: her flaws. One of them is 'doesn't take things too seriously,' but her entire motivation is pretty deep. I'm guessing it has to do with some form of abuse. With this in mind, I think that she would take things pretty seriously. She can be happy, but I don't think she'd necessarily be flippant.
Nice job on the backstory!! I only have a couple of notes. One, you mention that she's less trusting, but this isn't mentioned under flaws. I feel like this should be a very important part of her character, since he past motivated her in such an enormous way. Two, it's the same thing–more detail after-the-fact!! Tell me more about her relationships with her friends and her 'job' as a superhero. Other than that, nice work!!
Overall, I think that you have some excellent characters here. I struggled finding enough to critique, so that's good–and also why this is so sparse (sorry)!! I really think you just need to give the backstories a touch more love and you should be all good!!
I hope that this helps you!! :DDD