Headcanons as in things I think are canon... yeah. I think MinSung are actually dating lmao And I think for real that Hyunjin wants Chan to run a train on him. AND I guess the one that I would like to share the most is that I think Chan loves the kids in a way that is pretty romantic. Between platonic and romantic, maybe. But I headcanon that he has not let himself ponder it enough to realize (or rather, ADMIT) it's that way and therefore he continues living with his feelings untold because at the same time it's enough for him to observe them and love them like that. Like, he'sgreedy but his love and respect for them is even bigger so he holds himself back from it. So if you join everything together I think Hyunjin has let Chan know that HE is willing to go there and maybe perhaps mayhaps have they have explored each other bodies a little bit. Hyunjin and Chan. At the very least they are very aware that they want to and they are walking a very fine line between knowing and doing, enjoying that hard-core sexual tension, yaknow.
I think, for Felix (for ChanLix) I have said it before, that I think it all collapsed at some point and Felix's massive crush on Chan (that I believe wholeheartedly existed) dissolved with time. But I also think he feels nostalgic sometimes, when Chan dares approaching and doing something completely whipped that show he IS clearly whipped but it's like... way too late, and way too unserious/platonic/held back to be enough.
So uh.... those are my headcanons when it comes to SKZ ships. I'm not saying they are real, I don't have a magic ball to see everything but that's what I would bet for if I had to.