L2 to H1/H4: Question regarding status on 1st Oct 2013

[TeqGuy]

I am on L1B visa for Company A.My wife is working on EAD(L2 dependent).Company B filed for my H1B and H4 for my wife and it has been approved on 25th June. Meanwhile, my wife also has got her H1B approved from Company C and was approved on 16th May.
Questions:

1. On Oct 1st, my H1B with Company B will become valid and so will my wife's H4 filed by company B. My wife's H1B filed by Company C also becomes valid on that date. Does this mean she will be on H4 status on 1st Oct?
2. In case she is on H4 status on 1st Oct, can we do something now i.e. before 1st Oct so that her status changes to H1B on 1st Oct? Can it be expedited?
3. Can we file for cancellation of her approved H4?
4. Should she go out of country and enter on stamped H1B visa?
5. Can we file Change of Status request right now? Can it be filed in premium processing?

Would appreciate a quick response as we need to decide on course of action soon.