Originally Posted by
gojko88
Eastbound flights are usually a bit early, so I wouldn't be too worried about your connection. You almost certainly won't need to run.
In the unlikely case that you misconnect, you will deal with LH for rebooking - you can do that in the LH Business lounge (no Senator lounge for you unless you are Star Alliance Gold - the Amex Platinum is immaterial for most airline lounges in Europe).
Regarding carry-on vs. checked luggage, these days carry-on seems to be the smartest option regardless of connecting time, but other than that I don't foresee a specific risk.
I leave the remaining points to FRA experts
Actually AMEX has a deal on with LH that gives Platinum holders access to BIZ when flying Y and SEN when flying J. Centurion used to give access to FCL (not FCT though) but I don't know if that's still on.
Regarding connecting B non-schengen to A, I am not sure if it's possible to do it cleanly, even if unloaded in Clean B. I would expect the trip to be - take train to Z, transfer security, then passport control Z>A. If it is possible to enter Schengen B, then enter Schengen B, then take the tunnel to A.