> In * you seem to have designated *G lounges which may or may not be F lounges?? Is that right? And *S members don't get lounge at all?

To answer one of your questions:

*G have business lounge access. In some airports there is a dedicated *G lounge (e.g. Singapore) which is not a lounge for a specific airline. If you fly Y that's what you'll have to use. If you fly business you can use any * business lounge. If flying F of course you get F lounge access (you would not need to, and probably wouldn't want to, use the *G lounge).

No lounge access for *S (although I seem to recall something about LH Silver members having LH lounge access).