To me it's really straight forward how to handle both of these guys. Health permitting, this is what I would do.
Kopech - Hasn't pitched (outside of Spring Training) in 2.5 years when the season starts. If the season starts on time, start him in the minors, make him prove he can throw strikes. You likely gain a service year by doing what makes sense given his injury, development and the current roster construction (Sox will add another starter).
Crochet - Sox seem set on him making him a starter. Start him in Winston Salem as a starter. Let him pitch to around 100 innings as a starter in the minors. Call him up for the stretch run to be a bullpen stud. This way, you allow a guy who has never built up a significant starter workload to get a sniff of the routine. You max his service time. You get high leverage use out of him. You protect his arm putting him on a nice development path.
The Sale path for Crochet may make sense but...Sale is an exception to the rule. Not the rule. Sale is a freak. Sale averaged almost 100 innings his last two years at FGCU as their Friday starter. Crochet has 12 starts in his collegiate career. He has thrown less than 140 innings in NCAA/pro ball.
Also, just want to get ahead of this. Yes, I mentioned service time. Yes, I want to win. No, I don't get anything out of Reinsdorf saving money. This is a business. The decision makers operate within the constraints and rules of the CBA so my thinking will encompass these rules.