Ace and Dylan both have a great chance to be great pros, and have different challenges that they have to address.
I think the path for Ace is more straightforward with his size, shooting ability and range. Most guys his size are still learning to handle the ball at his age, and that will improve with training. They will do a much better job of getting him open and in a position to score, and will teach him what shots not to take.
With Dylan, he is going to be going up against much faster players in the NBA, so if they do not respect his 3 point shot, he may find it much more difficult to get to the rim. He also has to become a better playmaker, and improve his court vision to get his teammates involved and help them find better shots. On defense he will need to move his feet better and learn to stay in front of his man, because there is much less help.
Keep in mind they are both likely to end up on lousy teams. They will play a lot for teams that are in 2-3 year turnarounds, so their games should mature at the same time their teams are improving.