Andre Dos Santos
If you asked Owen what he thought of Andre, he would tell you that he thinks that he's a good guy. And genuinely, he does. Andre has his priorities straight and a good heart in him. On a human-to-human level, he thinks that Andre is awesome. When it comes to them being family, though, things get a little bit trickier because growing up, Owen was always so used to having the authoritative voice out of his family. Or at least when it came to Kylie. So when he and Nat moved in, Owen still wanted control over the affairs of the sibling group that now had grown to a group of four, and he had to adjust to allowing Andre to have some control there too. There's definitely still a little bit of a power struggle in that sense, usually with the boys both having the same end goal in mind, but different ideas for how to get there, that leads to some arguments, but overall, Owen gets along with Andre well enough.
Bella-Rose Rockefeller
Owen and Rose are very close friends, and it shouldn't be that surprising, considering that their families are close to begin with, plus, they're pretty similar. Owen finds comfort in knowing that there's someone else who feels like the weight of their family's reputation rests on their shoulders, and their shoulders only. He understands how stressful Rose must feel, considering that she's always been viewed as the perfect child, and the one who has to hold it together to make up for her siblings' slack, since he feels the same way. He's always recognized that she was physically attractive, so that's nothing new, but he really values the emotional and mental connection that the two seem to share too.
Brooke Rockefeller
Brooke and Owen were on much better terms growing up, than they are now. As kids, they were probably closer than he and Rose are now, but when Brooke's depression started to hit, Owen didn't understand what she was going through, and thought that she was specifically just pulling away from him. He took it as a sign that she didn't really want to be friends or hang out, and they grew apart, while he seemed to grow closer to Rose. Things didn't end horribly and he would love to be closer with Brooke again, but since so much time has passed since they were actually close, and since he's still unaware of why she seemed to drift away from him, he doesn't know if that will ever happen again.
Christopher Rockefeller
Growing up, Owen and CJ were inseparable. They were the definition of best friends, and often, Owen felt like Chris was more of a brother than a friend. They were both athletic, into playing sports and being active, and as kids, they had a lot of fun together. It was only when they were teenagers that they started to grow apart, with Chris becoming more involved in the party scene, and Owen maintaining his focus on school and his family. He often felt like a loser for doing so, especially when CJ would come back to him with stories about all of the girls he hooked up with, or the 21+ clubs that he managed to get into over that weekend. However, once they graduated high school, and Owen realized how much better his choices left him than Chris, he was glad he didn't succumb to that peer pressure, that was probably more self-inflicted than actual peer pressure. He never really felt bad for Chris' downward spiral, because he blamed CJ for not caring about his own well being and future. Owen feels like he could have done the same exact thing, but instead, he decided to be smart, so it's hard to have a lot of pity there. During the years of Chris' major partying and drug issues, Owen actually did cut off contact with him, but over the past year or so, they reconnected and are nearly just as close as they were before.
Haven Hewson
Owen and Haven aren't best friends, or really even friends, for that matter, but they aren't enemies. Their relationship is one that doesn't hold much weight because they aren't hanging out constantly, but Owen definitely feels conflicted about her. On one hand, she's this gorgeous girl who seems to flirt with him a lot (even though he knows that she does that to everyone). Any guy with a brain would push any of her flaws to the side for at least a night, to get a taste of her. On the other hand, though, he does feel like she's incredibly irresponsible and that at twenty-one, she should know better. There's no excuse to be getting into car accidents, drinking and driving, and just generally being reckless. What he feels like gives him a reason to dislike her even more for that, is that she seems to be a negative influence on Kylie, coercing her into thinking that it's okay, and even cool to do these sorts of things.
Kylie Jenner
Kylie is his half-sister, but since Owen doesn't have any "full" siblings, he would only refer to her as his sister, disregarding the technicality that they don't share a mother. Owen has always felt a need to protect her, because he feels like her mother's side of the family doesn't do a good enough job in doing that. In fact, like his father, he thinks they actually do the opposite. Owen feels like his family are the only people who actually care about Kylie's well being, and not how much money her latest scandal will bring them. He definitely has her best intentions at heart, but because he feels like she's being brainwashed by the other side of her family, he often feels like he has to act overprotective, rather than just normally-protective or willing to offer casual advice, to make up for their lack of guidance. Owen and Kylie are almost always butting heads because of this, and he'll willingly tell you that she's the brattiest, most ungrateful child he's ever met, but he still loves her.
Natalia Dos Santos
You can call them step-siblings or whatever, but when Owen thinks about Nat, he thinks about her in the same exact way that he thinks about Kylie. She's his little sister, and one who he feels like he needs to protect at all costs. Seeing tabloids and provocative covers or photo shoots that she does outrages him. He knows that she's an adult and that truly, she has a good head on her shoulders, but he just innately feels like people are out there who are going to hurt her, and that she's smart, but not smart enough to protect herself.
Valen Bautista
Owen has never had any direct conflict with Valen, so when they're around each other, he's civil, if not cordial, towards her. She's a pretty girl, seems to have some stuff going for her, and that's all good and well. What makes him wary of her, however, is that she seemed to come into CJ's life at the same time that he plummeted way out of reach with his drug and partying addiction, and that she's step-sisters with Haven, who Owen admittedly has mixed feelings about, but is sure isn't a good influence on Kylie.