Your potential leavers list is incredibly extensive- realistically, only a few of them will probably leave unless they get insane usage in RU/UU.
Dugtrio traps, big whoop. His attack is lacklustre and his defenses are nonexistent. There's a reason he ended up in NU and I see no reason for him to leave.
Gorebyss: I doubt it'll move all the way up to OU, but anywhere you go Shell Smash is a potent threat, so I don't really see any reason to move it up unless usage goes up- it is a threat here in NU but not an unchecked one.
Slowking: I think he might, since Slowbro is all the way up in UU, and he is a very good wall with regenerator. But not without his counters in this tier, so I don't think it'll be VOTED up there.
Lanturn has mediocre def and sp def and only managed to find a niche in NU. It can't do anything of note in RU or UU, and it's needed here to absorb Magneton's moves. I don't see it coming anywhere close to getting the RU usage needed to bump it up, or it as so strong a threat it will be voted up.
Rhydon: Yeah, and good riddance too!
Scoliopede gets decent usage in RU, and it will get more because people used it in NU and liked it and will start putting it on RU teams- it's one of the best Toxic Spikers out there. I'm really not sure about him.
Snover: Gtfo my tier.
Braviary: I hope not, because I love him. But I can easily see enough RU usage to bump him up.
Swellow: King of NU, can't hold his own in RU. I doubt he'll move up- you'll just have to deal with him.
Klinklang: I think he'll get enough RU usage to move up, and while I'm not a fan and personally think he's a b**** to counter, I don't think he'll be voted up due to the prevalence of counters like Camerupt.
Magneton: No. He belongs in NU, and will probably stay because he's not really as viable in RU.
Rotom-F: Are you kidding me? He gets a lot of usage down here because he's useful DOWN HERE. Nobody ever uses him in RU because of his meh speed, typing, and useless ability. He's SR weak, which cripples him severely anywhere, but he can actually do something worthwhile down here. I can't see him moving up w/usage or with a vote.
Absol is incredibly predictable and, while always dangerous, isn't taken as seriously in higher tiers as here. He'll stay.
Cryogonal: An incredible Sp Def wall and one of the few valid spinners in this tier. I can't see him leaving, though maybe he'll become popular enough in RU to move him up, but I doubt it. He does well here, but is of course insanely counterable. No reason to move him for balance.
Quagsire: Dear God I hope he moves up to RU. With so many set up sweepers/bulky attackers in this tier, he just shuts down so much of the tier. His stats are also too good for here, and is incredibly viable even in OU. He'll leave, hopefully.
As far as comers go:
Victreebel :D I hope he comes down, because I love him, even without sun.
The other two: Meh. Crawdaunt is pretty beastly banded, but slow, and Charizard's x4 SR weakness turns me off of him every time.
Sorry if I was harsh, but there's no way all of those are moving up.