Hello,
Coffee cups, juice boxes, etc. should not be in the Church. And I think that if the Priest sees that, it could be grounds for that Priest to refuse Communion, since the person isn’t properly disposed (breaking the fast). Pastorally, this should be handled probably by allowing it the first time, but after Mass instructing the individual privately that it was not proper and then possibly denying them after that. If it is a widespread problem, then the Priest could mention it during the homily that this was not allowable.
As for water bottles. Water doesn’t break the fast, so there is no problem. Just be sure to not slurp too loud. In fact, I take a bottle of water with me when I go to Mass (I have a medical reason). I do my best to not distract others by it - I keep the bottle out of sight and do my best to drink (when the need arises) without calling attention to myself.