Console lighting, idle, reverse gear

Hello.

I've already asked a few questions, but they've gone down in cruise matters, so I'll put them here again:

When I am idle or when I am idle. in P, so the speed fluctuates very easily up and down and sometimes it vibrates a little, is this the idle control valve ? Today it seemed to me once that he had pulsated at the intersection (very little), and then I tapped on the Lambda, but neither came back nor would I have noticed that while driving.

Then: I have done a reset of my "driving style" by plugging off my gear control unit (stupidly) (is that so, or ?), at least the switching points are now others (stupidly). How long does it take for the whole thing to adapt to its own style, should this ever be possible?

Then I have a rather strange thing about the reverse: if I insert it, the V8 sometimes (not always) fibrates quite strongly to extremely. But only in reverse. Light vibrations are usually only perceived in P or N when the speed is slightly variable. Can this also be the idle control valve ?

However, switching, starting and other players still go absolutely impeccable, except that he e.g. From D to R and vice versa it takes two seconds to get the "speed in".

Yes, and then something quite simple: I broke one (or two) pears at the console switches (seat heating on the right), so there is no red backlight at the switch anymore. How can I replace the pear, and where can I get it?

Anything else: If the brakes are "singing" high-frequency when pedaling very easily, but this is immediately gone when pedaling more firmly, is this due to the discs or can it also be because the linings are simply on the front side when cooking?

Last but not least: so far, my already at only a few 25 liters
In the tank started to beep and chase me to the gas station, which was annoying, since our build-up, he got used to it - until now. I am now on a good 20 liters, and the "Only more 50km" warning indicator flashes at the BC, but it does not (yet) come with the tank warning. What could this be about? Just luck and he comes in a few kilometers with it or could it have other causes?

Thank you for your help, the small problems seem to take no end ...

Best regards

Bastian