It is reasonable not to discard stuff that's already there. OTOH, a 1 ounce tube of antibiotic ointment provides dozens of applications, and might fit into the space where the gauze is housed. Similar argument for diphenhydramine and loperamide. IIRC, Usual dose for antihistamine is 25-50 mg every 4 hours, antidiarrheal is 2 tabs after first episode and one after each succeeding episode to a max of 4 per day. You have about one days treatment for one patient in each category. Is that enough? depends on the severity of the illness, and if the patient can get to a definitive care provider within a few hours. May not be economically feasible to provide more than this in a first kit. Hemostats are useful for removing bigger splinters, and have a high general utility value: emts and nurses generally carry both, and it's probably hard to get into trouble with them. Understand that bp cuff/steth is too bulky, but a little digital thermometer is still a good idea, and quite small. Hard to reconcile the competition between cost and comprehensiveness: providers like me always want more stuff. If you are not getting complaints from the users, you are doing just fine.
Oh-coban/vet wrap is great for securing dressings, not so good for elastic bandage applications: hard to reuse coban, while an ace lasts a long time.