Can't recall Presti. But Reid started as a forward I'm sure. But came in to the side and was given a long run in the side as a key defender after impressing in the VFL in that role.
Knowledgeable (and not trolling) Dogs fans have dismissed Jones as a defender whilst he was still there. But then again I think they are judging on a small sample size. He could certainly play key defender before he was drafted. He's athletic, has good size, neat skills (and seems to have improved his goal kicking) and can certainly take a grab at times. So really he's got the traits to play at either end. He can't seem to find the ball or win enough contests as a forward, so sometimes moving to CHB helps. But if you're not physically up for it at CHF then you hurt the team even more in the backline.
I'd persist with him forward. A good honest 3rd forward working in a system with Henderson and Casboult might be pretty handy. More useful than a middle of the road CHB which can usually be found easily enough. But if he's not doing much forward I'd give him a sustained run in the VFL and AFL as a defender.
Prestigiacomo has a career total of three AFL goals. I doubt he was ever a forward for very long. Reid made his career early in 2010 playing back, his first full year was down back and he's stuck there for most of the time. Reid is also a much more skilled footballer which makes him more adaptive.
I understand Jones has had some junior experience playing back but junior football is often loose and defenders are often judged on their athletic potential rather than stopping talent. At AFL level, Jones doesn't seem physical enough to play down back. I also think he'd be inferior to Jamison and Rowe which means he'd be playing as a third tall defender, which seems to be an odd move. Carlton have a hole in their KPF set up and if Jones doesn't fill it, then he seems to be not relevant to their current or future plans.