The second one is on the area with the stone heads on the ledge, if facing the jungle entrance.
The third one is on the ledge leading to the bridge near Gremlin Buzz's location and the well.
After painting in all three lanterns, the wooden door he's behind opens. After he's freed, he fixes the dam and the Thinner river permanently dries (as opposed to the alternate method of painting in a gear on the dam and only temporarily drying the river for 30 seconds at a time).
His name may be a reference to Buzz Lightyear from the Toy Story movies.