In the short term I think Alcantara has to be parked at Iowa. There's just not playing time for him unless/until there’s an injury or Shaw goes into a tailspin. It's also worth noting that he appears to still be developing, as the season progresses he is slowly clawing back the contact rate he sacrificed to juice his launch angle. Fingers crossed that trend continues.
Medium-long term I think Alcantara fits into the puzzle with the glut of infielders, and I'm hoping they find a way to keep him. This winter you have Happ, Suzuki, and Kelly all hitting free agency. So that's two full time outfield spots, plus whatever DH time is freed up by Mo presumably getting more time behind the plate. You can't expect to hand all of that time off to the kids, but you can probably do 2/3s?
I think broadly there's a choice between Shaw and Alcantara for a full time OF spot, and then there's a choice between Shaw and Pedro Ramirez for the supersub role Shaw's currently in. I'd probably go Alcantara/Ramirez, though there's a lot of time for that to change. But broadly I envision something like this:
Out:
Happ, Kelly, Conforto, Shaw (trade)
In:
Suzuki (extended), Alcantara, Ramirez, another veteran LHH OFer
Again it's too early to get hung up on specifics but I really like the range of skills adding Alcantara and Ramirez to the roster brings, and at the same time I suspect Shaw would bring back a pitching haul.