My opinion on the high beams is if you are a driver and this buses lights are shining in your eyes daily, then call it in. If your comment is only based on an observation as a passenger and has not effected your personal life directly, then just move on. Pick your battles and this one isn't worth it.
As for the cell phone, you've said you saw it once and not since. Not worth it. You may not be old enough to have kids in school, so let me use this as an example. Consider that many drivers are working a full 8 hour shift. No lunch or coffee breaks. Personal lives do spill over into business hours. Could be a problem at home or school. You don't know. You would also be upset if driver pulled over, stopped and got out to talk. Yes talking on the phone is illegal and not allowed but you don't know the situation. For now, give the benefit of the doubt and let it go. If you were to see the same driver always on the phone daily, then yes, it needs to be addresses.
Always choose your battles. Remember, driver are only human and sometimes make mistakes. Calmly discuss with driver. Don't be confrontational. You'll get nowhere. Your reports can have consequences. Think first. Do you want him in trouble or to just stop. To report or to discuss. Hey, if he's an ass, then report but if you can discuss it and he stops it, then mission accomplished.