Area 1 Path 2 has 2. One is in the SE corner of the first room. One is to the right immediately after leaving the roller tunnel. The latter is problematic, since the floor slope causes bombs to roll beyond the deposit, and if you do time it right, the resulting ores roll into the tunnel, so it's hard to retrieve them without being hit by the roller.
Area 1 Path 3 has 2. When entering the sole room, one is immediately on the right. One is on the left near the exit.
Area 1 Path 2 has several. There are 2 to 3 cave wisps near the obvious Erg Pot. In the final room there are initially 2. After disposing of those, 2 more spawn with the mid-boss.
Area 2: 2 or 3 will usually spawn when the Erg Pot is broken, but they sometimes seem to be missing. Try luring them to the entrance to the narrow passage on the NE side of the main room. Mobs cannot enter this passage, and the wisps will hover around the entrance, making them easy to bomb.
Area 1 Path 4: It is difficult to cross the first bridge before it is cut, and the fall can cause significant damage. It may be safer to slide down the steep slope to the right of the start of the bridge and use the ladder to ascend the other side.
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