What is the plural of "potato tomato hero"? Why

What is the plural of "potato tomato hero"? Why

1. Add es to the things ending with O, such as tomato, potato, mangoes, hero and - es after hero
2. Add "s" to "inanimate" things ending with "O", such as radio, piano, photo and - S
3. Some nouns, such as volcano and tobacco, can be plural with - s or - es