Not so sure about that Gus, have a read of this...
AFL Free Agency, Trade, Draft & Season News From my interpretation, although Melbourne have committed to Jack Viney as a father/son selection, they have not put pen to paper on a contact, which can only be done after he is officially drafted to the club.
IF melbourne are stripped of the first three rounds in the draft - then Jack Viney will NOT be eligible to be drafted by Melbourne, instead he would go into the draft where he could be obtained by anyone.
The only way Viney could be obtained by Melbourne, is if he lasted until the fourth round, which would be highly unlikely.