The 343s will be here for the medium term, although by 2015 the plan has them all gone. By 2012/2013, all of North America will be served by 777-300ERs.
As for JFK, the 777s will be going in November doing the yet-to-be-launched evening departure out of HKG. By the end of the year when five 777-300ERs have been delivered, both the daily non-stops to JFK will be the 777. The YVR-JFk flight will continue to be the 744 for now. After JFK, the 346s will be moved to launch a YYZ non-stop although this will only be for a short time before the 777s go there too as the 346s are moved elsewhere. The official line if that the 346s will leave although there are rumours that once ILFC offers a good deal, they will be retained. There are rumours also about us picking up three ex-South African 346s too
The A330s will be around for quite a while.
Also a flight number has been assigned to the mysterious JFK-LHR flight...CX840/841. No new rumours I have heard about this starting...just the appearance of a fliught number and 777 as aircraft type.
The October schedule now shows a 2nd Daily SFO flight, timings as follows:
CX870 HKG-SFO Daily 1410/1135 744 (New Flight)
CX872 HKG-SFO Daily 1625/1350 744
CX873 SFO-HKG Daily 0120/0625+1 744
CX879 SFO-HKG Daily 1335/1840+1 744 (New Flight)
Flights will also continue into the winter schedule:
CX870 HKG-SFO Daily 1410/1005 744 (New Flight)
CX872 HKG-SFO Daily 1630/1225 744
CX873 SFO-HKG Daily 0010/0655+1 744
CX879 SFO-HKG Daily 1205/1855+1 744 (New Flight)