I went back and replayed the part after the investigation, where you can get drowned, and I cant find anyone else other than the pizza delivery girl, that could be Lel. Idk why she would be though.
Ok, spoiler ahead (or at least, what I think it's spoilers, and might be completely wrong):
I think the difference between Kayden and the others is that Kayden is manipulative with everyone. And in an abusive partner kind of way. He tries to break everyone, belittle them, blame them, so they are a broken mess apologising to him.
Everyone else mostly treats Sparkle different degrees of badly, but to a degree you can justiy it with Sparkle being strange, phasing out etc. With Kayden you know that if he didn't find one justification to be an arsehole, he'd find another.
Not really.
Actually, Kay is a control freak, but he isn't outright abusive. He's a manipulative s.o.b, so finds a way to have control with actually very good arguments (which of course, noone with common sense would accept). But in the end, he never forces anything on anyone, he plays by the rules, and mostly is because of the group's "benefit".
the problem is, he does whatever it takes to keep the group togheter, without acknowledging that the group might shouldn't be togheter, or that they might be better separated, and that's his egoistic aspect.
Basically, because like most manipulators, in his core, he wants acceptance and not be alone. This shows up several times, and that's why Dave is SO good at making dialogs and characters.
On the other hand... Panki is ABSOLUTELY detached of you if you're free use. She actually tells you that, you're "just an accesory". Kayden tells you exactly that at the beginning, that everyone wouldn't care about Lel, just like they don't care about you now.
So, in the end, is Kayden doing something good? Not really, but he has a reason to be nasty: indeed, had not be that nasty with Lel, she would be nothing else than an accesory.
Twisted, but he makes it work... and he's not happy about it.
Lel herself is not really caring, she takes control quickly, and pushes you because you're free use.
Roopah is straight abusive, and again, Kayden is the one that tells you about.
Harmony is kinda vague, but she shows some sort of controlling attitudes too (taking advantage of Sparkle's weakened will with the spell).
Leigh is simply an asshole.
Champ and Twig would get your ass (literally) at the slightlest chance without much asking.
So, what's the difference?
Kayden always gives you options.
He doesn't pushes Sparkle ever, and while he might convince you or not, it's always an option.
Even when you're free use, he's the only one that actually congratulates you, the only one that scolds you but gives you second chances, and several times he gives you the option to quit or change this or that.
And it's the only one showing some kind of remorse if you have some setback of any sort.
