Hi guys, I also face the same problem, but I went and bought some "rubber softener" oil or you can use those tyre shine oil to wipe at the rubber areas of the car (i.e. the passengers door, window rubbers...etc.)
My E60 previously also had this problem, but I uses the rubber softener or the tyre shine oil to wipe it.
This actually fixes the problem for me for the squeaky sound, as for the rattling sound, it's either the seat belt not place properly or the rubber issues,
I solved mine, hope it helps for ya'll.