Excellent kit! The biggest problem most people with medical training have is carrying too much. You need to tailor your tools to the job at hand. The most likely scenario is a muscular skeletal or soft tissue injury. Handling those injuries should be your prime concern. The only things I would add would be a eye shield. I would also ensure your rescue kit has a durable space blanket and a breathable bivy sack. The bivy sack can be your survival shelter. The last and most important item is a fire starter to keep you warm in the event your patient is hypothermic or you have to overnight. Most importantly is to learn to use the equipment you are carrying. Nothing worse than not treating a wound because you didn't recognize it or didn't realize you had the tools to treat it.
Full strength Asprin 325 gr. would serve double duty. The intent of baby aspirin with heart patients is to thin the blood. A full strength Aspirin would do the same and fend off some of the pain. Learn everything about your meds before you carry them or use them.
I do not recommend coban in the backcountry as it compresses into a hard ball in your pack. Israli bandage is a better alternative. I also would ditch the triangular bandage. You could can improvise with othe pieces of clothing.
I would ditch the Israeli bandage for a NAR ETD. It's compressed smaller and does the same thing. True you can improvise a sling, but Triangular Bandages can be used for a lot more than a sling. There is a reason military medics still carry triangular bandages and it's not to be used as a sling. Learn to use your equipment!
I use the jacket trick to immobilize shoulders and wrists. Tuck the arm in on the abdomen, ( the arm is out of the sleeve). The rescuer zips the jacket and tucks it under the arm. My saying is: the best first aid kit is the one you bring with you. ( lighter the better for me). I agree that it has to be tailored to number or participant, duration , activity, prior medical conditions…
Ask questions like this in your WFR class as well. One person perspective is not gold (unless it’s medical direction). Use what you’ve learned in your training to build s good first aid kit to treat what you are trained to treat. Look into a TQ too, bleeding is a quick way to die in the backcountry-cold and bleeding don’t go well together. EMT/ WFR