My front passenger seat rattles too, not a lot you can do with that its down to the build quality, though the rear seats should be fixable - they may have been removed so make sure theyve been put back properly.
The knocking could be anything maybe the steering rack, but im not a mechanic sos just a guess.
Whistling noise could be from poor allignment of the door or the window not going all the up when closing.
Best thing to do is take it to your dealership and make them have a look at it, should be under warrenty still if its not an import.