So what's beyond the universe? Do the laws of physiscs even exist outside the universe as they do inside?
By definition, the universe is all of space and time, and all its contents. So nothing can be "beyond" or "outside" the universe. Your questions are dividing by zero.
The observable universe is everything that can be sensed in any way... i.e. that can have any kind of effect, however small, on the observer. If something is not observable, it can't be sensed or affect you, so it is entirely irrelevant and unimportant. Similarly, it's irrelevant whether the laws of physics exist there or not. However, our knowledge of the laws of physics is incomplete, so there may be "stuff" in our universe which is currently undetectable, and we may be able to expand the boundaries of our observable universe.
The same applies to the concept of the multiverse or parallel universes. If something is in another universe, it can't affect you, so (a) it's not observable, and (b) it doesn't matter (pun intended).