As far as the ABS, you need to get a factory level scan tool that can look into the modules; a generic scan tool won't do anything for you. If you hook the car to a GT1 or Autologic, you can communicate with the ABS module, and see if there are any faults. These will not necessarily throw a code that a generic OBDII scanner will see. If the proper scan tool can not communicate with the ABS module, which is not at all uncommon on these cars, then it's time to replace or rebuild the ABS module. There are services that rebuild the modules for a bit over $100. But not all are rebuildable. The one on my 528i was, the one on my X5 was not. But the rebuilding service supplied a working module for $400, a LOT less than a new one. Once the new module is installed, it then needs to be coded. Not particularly accessible on the X5.

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2014 BMW 328i Xdrive
2011 BMW 335i M-Sport
2008 BMW X5 4.8i Sport
2000 BMW 528i 5sp