Was anything they consumed poisonous in some manner?
- Needs to be rephrased.
Were the ice cubes in the bourbon composed of anything besides an average mix of water and minerals in a usual ice cube?
- Yes.
Do the two cowboys know that each other is an enemy with the crimelord?
- No, but that's unimportant.
Are either cowboy aware that the crimelord is in Normalville?
- Yes. They're just too thirsty to wait until the next town.
Is the crimelord in some manner responsible for the death?
- Yes.
Is the cowboy that left first dead or injured in some manner?
- Yes: he got into a fight with some bandits a few days later and got a bullet or two to the head. But for the intents of this situation, no
Is one cowboy responsible for the other's death?
- No.