Robert is going to be a transformational star if he stays healthy. Eloy will win a batting title and regularly contend for batting titles. People don't appreciate just how good those two guys are. The beauty of Robert is he'll also be very valuable in the field. IF they are healthy I don't see anything getting in the way of either of those prognosis. Moncada will be a, at worse, well above average guy, and given his OBP capabilities, power and ability to field, he too could be Robert (albeit, I put better odds on Robert because I think he is more elite defensively).
The fact that you also have Tim Anderson, in addition to those players, gives me a lot of hope because that is four guys who are very valuable. I won't comment on McCann and whether he can maintain, but he looks like a starting catcher.
I am more optimistic on the Sox than most, but I actually think this year has gone way better than expectations, even though Rodon and some other prospects have struggled. I can't project out Collins and others because I could see them working out but I could also just see someone like Collin's bat speed not being enough and him just being a lousy player (who if he is stuck at 1B just doesn't play). Madrigal I see being a league average guy at worse, because I think he'll do enough little things that play and if the hit tool comes around (like it can) he becomes one of those sneaky good players (who is probably always underrated by metrics) but when you surround him with the other guys I mentioned, great.
And than there is Tillson, Rutherford, Cordell, etc.
The big wildcard to me is the rotation as I have no idea how that could go. While Rodon is injured, Lopez and Gio have flashed ability to be middle of the rotation guys (they could also be too inconsistent and end up not either). I doubt either is a top of the rotation guy, but it could happen, this year will tell us a lot more (imo). The key to me is how good Cease and Kopech are as they both could be aces, but that is a major questionmark and then you need to find depth around them (cause pitchers get hurt). I don't know if they'll end up having the elite pitching which might require them to trade for it and/or get it via free agency (and that is hard to do). But in this league, the most important part of making the playoffs is having a good lineup (which I think they are well on their way to doing) and a deep rotation filled with a number of quality guys (they don't have to be great, but depth is huge as it will enable you to win a lot of games surrounded by a good lineup).
That same depth might not put you over the top in the playoffs, but the first step is getting into the post-season regularly. At that point you need to be hot and having front of the rotation aces who can win games on their own becomes key in increasing your chances at ultimate success.