1. You may be seeing instances where the reporter can't remember who was being offensive. When that happens they blanket report the whole team to make sure they report the offender.
2. This one is pretty iffy and you must use extreme caution when dealing with these. Do they have all boots or wards? If so, they were probably intentionally feeding or at the very least assisting the enemy team. Some cases it's very hard to determine this and it's best to just look at the rest of the games for other infractions.
3. The problem I see here is the "attempt to communicate" is done in rather poor fashion. Was he being a jerk? If he is, then it's punishable. If not, then move on to the next game.
4. A while back, there was a bug that prevented the name from being displayed in the cases currently being judged. Probably just a matter of getting its wires crossed during an update or something. Afaik, it was fixed and the name should be displayed correctly on the games that it was reported as such. I can't verify this though as it has been forever since I've had to judge an inappropriate name case. Generally, you could hope for the notes to contain the name as well, but that's usually a miss most of the time.
The general rule of thumb is to ask yourself, "Would I want to play with this person?"
I also like this gem. "Don't be a jerk."