Desertcamel,
I don't see any reference on why you couldn't use LNAV to fly a LOC approach, as a matter of fact the NP section states that: for a LOC, SDF, bla-bla approach the recommended roll mode for final approach are: LNAV or LOC . I agree with the personal technique to intercept the LOC in LNAV especially if it's a large inercept angle, but I personally would track it in LOC mode, since that is the most accurate, and even the FMC goes into LOC-GPS updating when it has a valid Localizer signal associated with the destination runway, below 6000 feet, less than 20 NM from the navaid, withinn such and such degrees, the exact number I can't recall, therefore your LNAV track is updated to the Localizer anyway... So you can use LNAV if you so desire, works fine, just make sure that you don't parallel the Localizer....
As for the second part of your question, I think they ment to write it as including ILS, LOC, SDF, etc, but I'm not quite sure, tried to read it 3 times now, and can't get my head around why couldn't you use it for all those approaches...