Is it possible to get infected with the amoeba, Naegleria fowleri, through your ears, or is the nose the only way it can enter to cause infection? How commonly is it found in your stool as well?
Ears? No. The tympanic membrane (eardrum) is a watertight barrier between the outer ear and middle ear.
In short: Don't huff warm lake water too deeply through your nose, and you'll probably never get it.
You shouldn't find it in your stool. Other amoebic infections can be found in your stool, as they can attack the lining of your intestines, but Naegleria, specifically, will reside in your sinuses and brain until you die or receive treatment.