It definitely sounds like a module issue screwing with the K BUS.
I had a similar issue on an E46 many years back.
There's a central connection block for all the modules K BUS network usually on BMWs. I know its on the fuse box on E46s (not looked on the E85 but id bet its in the same place). If you disconnect the wiring plug for the modules one by one, when most things spring back into life you've identified the offending module. Its just a case of then identifying which module that is, usually by seeing which functions still dont work and working out what controls them. Obviously its easier with proper diagnostic software if you have it. With software and a K BUS issue INPA/ISTA D etc will only see a few modules usually, when you unplug the offending module all the others (minus the one you've unplug obviously) will show up on a scan again. Its then easy to work out what modules giving the issue as its missing on the scan. Then youve just got to try and work out if its a wiring issue or the module itself, however in reality its nearly always the module itself. Once you've worked out the module you can usually replace with a used part to keep costs down, but it will need coding in virtually all cases.
Hope this helps