I am arriving off CX First Class and connecting to a CX or KA flight in Business Class. Can I access the First Class lounge during my transit?
Yes. You will be issued with two lounge invitations when you check in for your flight, one for use at your outport and one for use in Hong Kong. Your Hong Kong lounge invitation will clearly display an invitation to "The Wing/Pier/Cabin/G16 Lounge - FIRST CLASS".
There is some discussion at this thread regarding long transits between a First Class and Business Class flights and lounge entitlement: http://www.flyertalk.com/forum/catha...y-transit.html