1 Fresh drinking water location
The Fresh drinking water is located in the pond with the waterfall in the first area. Just get inside the water next to the waterfall and you will get the water. Note that you must have the empty bottle first.
2 Seagull egg location
The seagull egg is located on the top of a tree near the pond. To get to the top of that tree, you will have to climb the slim tree next to it then make a jump from the slim tree to the other tree.
3 3 fish locations
The fish can be obtained from the open water in the first area where you got the fresh drinking water. Get into the sea and start swimming around until you find the 3 fish.
4 2 coconuts' locations
You can get the coconuts by hitting some trees. Lock your attack on a palm tree and give it fa ew hits until coconuts start to fall.
5 First mushroom location
The first Mushroom can be found in the second area that has the raft. It's near that wooden tower that you can climb just in between the bushes. (See Why Playstation 4 is good?)
6 Second mushroom location
The second mushroom is in the cave right next to kairi. You need to push the stone to the side first then get inside the small cave to get the Mushroom.
7 Third mushroom location
The third Mushroom is located inside the cave with the drawings on the wall. The cave can be reached through the hole next to the pond with the waterfall where you obtained the fresh water. (See Why does the PlayStation move controller change color?)