I actually thought about this A LOT for Seventeen. My bias group is actually EXO but Seventeen just fits the young, fresh trainee image better so I could see them on the show better? This is going to be long lol
S.Coups would do pretty well, imo, since he has a pretty face, solid dance skills, an okay singing voice, and decent rapping. I think he'd get sorted into C -> B, and would get into Top 22? He could get pushed into top 11 with a good leader edit though.
Jeonghan would get a lot of hype for his eye-catching visuals, but I think it would die down as the show goes on for his average talents (decent dance and vocals) until the crafty scammer side of his personality is shown. That might get evil edited, but in general, I think most people find it funny and clever. C -> B, Top 22.
Joshua is one of my biases, but I don't think he'd get too far :( He has a sweet voice, but he's probably Seventeen's weakest dancer, and he's pretty shy when he's not around his friends. I think he'd get some attention for visuals and some international hype for speaking English, but other than that, he'd get swallowed without screentime. D -> D, Top 35.
Jun unfortunately probably wouldn't be very popular, judging by how underrated he is even in Seventeen. He has fantastic dancing skills and a preternaturally beautiful face, but his personality can be swallowed up by all the extraness that is the rest of Seventeen. B -> B, Top 35.
Hoshi would do great! His dancing is amazing, and he'd get attention for choreographing his group mission songs. He also probably would cry every elimination, but he has the cutest crying face ever that is actually stan attracting (see: knet reactions to him at Seventeen's first win). I think he'd be like Chungha, slowly climbing the ranks and getting into the final group by the end. A -> A, Top 11.
Wonwoo is a bit tough to sort. He's a good rapper with a nice stan attracting deep voice and gorgeous visuals. He's also a great dancer, and his singing is surprisingly nice too. But I think his SNSD scandal would affect his chances, and rappers aren't that popular in general. C -> A, Top 22, maybe Top 11.
Woozi!! I think he'd do well just by pure talent. He can sing nicely, his dancing is some of the best in the group, can rap a bit, and would obviously get a lot of hype for producing or arranging his group battle songs. I think he'd also have a Chungha-esque ascent, with slow recognition for his skills pushing him upwards. A -> A, Top 11.
DK has a fantastic voice, solid dancing, a great personality, and a nice visual, but I think he'd be everyone's underrated fave that just misses out on Top 11 :( I just don't know if he could pull off the Yeonjung edit, and even then, Yeonjung just barely made Top 11. B -> A, Top 22, maybe Top 11.
Mingyu would get in on visuals alone lol. He also is a decent dancer with decent rap. But his bright, earnest, Ming-housewife personality would shine through, and I could see some clips of him cooking or doing the hair of other trainees getting a lot of attention on the show. D -> C, Top 11.
The8... I'm honestly not sure. Depends on the image Mnet edits him into? He's a great dancer of course, but I can only see him getting far with a good edit on his personality, which is hilarious, i.e. the imma situation on YangNam. Kind of like how the Stone Nayoung edit pushed her wayyyy up when she wasn't noticed at all before. Also, his adorable best friendship with Mingyu (who definitely would be popular) would probably get him popularity if it was shown. B -> B, Top 35 or above depending on the edit.
Seungkwan has a wonderful combination of amazing vocals, decent dance, and an amazingly sweet and witty variety personality. I think his higher initial popularity from his personality would make him more likely to get the Yeonjung edit than DK, even though I prefer DK's voice more. But I'd be afraid that his funny persona would get him a bad edit or hate a la Jisung :((( B -> A, Top 22 or Top 11 with a good edit.
Vernon would get in by visuals. He got SO MUCH hype at debut for them, and his pretty solid rap and dance skills would keep his popularity up. In general, his personality is a bit more lowkey than the rest of them, so it would be hard for Mnet to evil edit him. B -> B, Top 11.
Dino is an amazing dancer with solid vocals and rap and a cute personality, but I don't know if that's enough to put him in Top 11... Cute maknae characters like Small Woojin and Hyeri (even though she was actually pretty old lol) get love and screentime, but not enough to push them to the top. Maybe because the image of cute baby puts them into too much of a box and doesn't let people appreciate their talents? He'd be A -> A, either Top 22 or Top 11.
Whew that was long!