Ha has been referred to as the best defensive CF in the system. I don't think he has been hitting well enough to be projected to be more than a 4th or 5th outfielder. Silva is said to be one of the best athletes in the system, and has shown some power this year, but as you say, he is a hacker and that will probably prevent him from being a regular in the ML. It was hoped that he could play second base, but reports on his defense there haven't been encouraging.
Unless Soler begins to actually dominate Daytona, I doubt that he will see Tennessee this year, other than perhaps a late season move to end the season there.