These are mutually exclusive requirements for the most part. A has been discontinued by AY and IB (and never offered by MA), so only BA and AA have A flights trans-Atlantic, and 90% of AA flights offering A are ex-LHR (since that is the primary market for First class travel). IB has a dozen TATL flights that avoid the US (half to NA and some to SA, which is an extra continent). Canada is served only by BA and after April 1 by MA. The CX flight YYZ-HKG makes a technical stop in ANC and goes through US inspection of pax, so if you are on the US no-fly list you won't be flying YYZ-HKG. YVR-HKG does avoid the US and has no such inspection. Finally JNB-MAD is well served by IB, so you can avoid LHR there, but only BA flies A to anywhere in Africa.