You're expecting to see movement far too quickly even for hydro. As for transplanting I've not noticed any setback from that. Usually they droop for the afternoon after transplant but pick up the next day. However I've only been growing since 1996 so I may not have seen it yet
I'll keep observing.
If you do choose to keep the one in coco use liquid fertilizer. Also when you start with any other inert substrate use liquid fertilizer (even if you need to dissolve dry ferts in liquid prior to watering). Measure both the EC/TDS and pH of the solution prior to use and make sure it's within the right parameters or it will be unavailable to your plants as you don't have a microbiome set up yet.
The problem you have with soilless vs soil is that they have two different watering processes. You can't treat soilless like soil and vice versa. That's why so many amended coco grows fail. It's like trying to graft the head of a dog onto a fish. It's a fraught amalgamation of diametrically opposed needs.
As I mentioned previously I have a friend with a Ph.D. in Biochemistry who can grow pot in anything (after his lifetime focus on plant physiology I'm not surprised). He's successfully used MG because he had it laying around. Cannabis is just a plant and not a particularly picky one. So use what works for you.