It sounds very much like you are beating your head against a wall. I know how very difficult it is to just do your job to the best of your ability and leave it at work, but it sounds like that is your only option if you are to remain there and remain sane. Unless you are directly accountable for their actions (and it does not sound as if you are) leave them to their own devices.

In an ideal world people would listen when there is a better way of doing things, but in reality most people hate even the smallest change. Even common sense things, like getting all of your supplies at the beginning of the day, some people insist upon going to the supply room a dozen times a day because "this is how I've always done it".

The only person that you can change there is yourself and how you react to these things. The company must give you a safe working environment but if you're the one going in telling them how x, y, and z could do their job better you're the one they're going to get irritated with. It doesn't matter that you're right. In my opinion the only way to survive there is do your job and let their supervisors worry about their job performance. If their behavior is making you unable to complete your job, ask your supervisor how he/she would like you to proceed in that instance. Approach your supervisor in a calm manner and say "I am not able to complete my project because I have not been able to get that report from Bubble head, what would you like me t do?" Avoid using the words "always, never, again". If they are harrassing you at work, complain immediately to HR.

As for lawyering up, at this point in time I don't think you have a case. Right now it sounds like the only thing the company is guilty of is hiring jerks. You can't even prove that it was someone that works with you, let alone that it happened on company time or property, with company resources, or that the company could have in any way prevented the problem. To have a case you must have a specific complaint about a specific person(s) that they failed to deal with.