As Infamy said WAT, most other teams can afford the luxury of letting their kids get experience in the VFL, then bring them in for a taste of AFL, then drop them back if they're struggling a bit and not have fans write them off as duds after 3 games (eg. Matt Dea). They're not required to dominate games so early into their careers.
With Melbournes improvement, there isn't the pressure on them anymore to get Jack Watts into the team and kick 5 goals a week. Jamar's form means their young rucks can go about it at VFL till they're ready.
We're going so bad at the moment that if a kid hasn't shown anything in 10 games, some want to move them on and try our luck in the draft again, only for the same thing to happen.
Going through your list:
Edwards - keep, he keeps improving.
Connors - keep
White - delist, he's worthless
Collins - keep
Farmer - keep
Nahas - keep
Graham - delist, he's worthless
Hislop - reports are that he's doing well at Coburg, still only a 20 year old - keep
Thomson - Old enough now that he should be a regular - delist
McMahon - delist
Morton - i'd trade this guy and he might get us an early pick
Post - keep, only his second year
Rance - keep
King - delist