1. I believe the six month validity issue deals with a passport's expiration date, not the visa's, so IMO your grandmother should be fine.

2. In my experience, there are always Cantonese-speaking crew on the HKG route. However, there is no way to guarantee that the pax will be served by a Cantonese speaker.

3. I believe the only choice for escort is to request wheelchair assistance. I did this for my parents (on BR), even though they didn't need it, so that I'd have some peace of mind with their going through customs here at LAX TBIT.

BTW: Why not have grandma travel on CX? The language barrier thing was the primary reason why I had my parents travel on BR instead of UA.