Data loaded into the FMC is always the same, and thus not dependant on the direction of the flight. I.e. data for the whole world is loaded.
That absolutely makes sense, otherwise you would have to load the FMC with new data when having an aircraft change on short notice (from east- to westbound).
Whilst many airports are stored in the FMC, sometimes it contains just the runway data and not the approaches. In such a case I would go with the method mentioned by Checkboard - of course modified to your aircraft/FMS type; In case of a diversion (especially during emergency) there is not much more that I need than the RWY info and ILS information (course, frequency). Personally I do not need a magenta/green (or whatever color is displayed on the ND) line to fly an approach
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