I just noticed the word ‘poem’ in your list. That isn’t an exception. It follows the rule. It says /O/. The rule is that it MAY be used at the end of a word. That doesn’t mean that it can’t be used in the word.
It’s just that “poem” isn’t “pome”, but “poe-em”. Not the same sound you have with “doe”, for instance. And that just made me think of “does”, “duhz” the verb that is, not the plural noun. I had better stop now. “Canoe.” Stopping NOW!