As far as I can remember, on the A330/340, the main wheel weight on wheels switches do not have to be "made" for reverse to be selected. I'm not even sure that they do on the 320 series. As I say - I am without FCOM at the moment so can't say for sure. The transition to ground mode starts at around 100ft RA dependent on type.
As regards bouncing - yes it's perfectly possible - I've done it!!!!!!! Oooops!!!!! On the bus, unlike other types, the spoilers will remain deployed during a bounce, unless either thrust lever is advanced. This does make for a firm second touchdown!!!! The 330/340 is very hard to bounce though - I did it on the the 320.