You’re Stranded on a Desert Island (not dessert)

1. Knife -- I can make most everything on that list or some workaround if need be.
2. Hand saw -- more efficient than the knife and assuming no rescue ever, reduce wear on the knife
3. Tarp -- for mobile rain protection assuming significant waterfall on an island.
4. First Aid kit -- could be higher depending on circumstances, but the number and nature of the equipment would have many more uses than any other non-essential items.

If it wasn't a big rain area, then the pot might make more sense than the tarp.

Also, it isn't specified, but I assumed that things like the insect repellent or water purifier wouldn't be replaceable before rescue.