Would anyone be able to clarify what the most recent policies are across LH group airlines, for the extra *A Gold bag on Light fares for Transatlantic itineraries?
(I see there's been lots of threads in the archive about Star Gold baggage, but most of them generally discuss intra-Europe flights)

• For LH, I see their website clearly shows TATL Light fares get a bag (although the baggage calculator doesn't show it) - "Star Alliance Gold customers on intercontinental flights, the first item of baggage on the Economy Light fare is free of charge"
• What about for LX, OS, and SN? Seems like LX and SN are a hard no, but I've seen mentions that OS might share LH's policy, but couldn't find anything officially?

Also a few other questions:

• U.S. DOT Regulation 399.87 apparently doesn't apply to "baggage from status" - does this mean on a round trip ticket from USA to Europe, with outbound checking-in on UA/AC and return on SN/LX/OS, the return flight wouldn't have a baggage allowance? What if the return was SN/LX/OS check in but connecting to UA/AC?
• For TATL flights to/from the US, how strictly do the airlines enforce the carry on size and 8kg weight? (I hear LX is particularly bad about this?)
• Does the LH extra allowance extend to +1s on the same PNR? I know on UA it does, since its the "normal" policy, but is that different for LH where it is almost like a "special exception"?

Thanks!