H4 to H1B transfer and start date for job

Hi,

I (H1B) brought my wife and son on H4 during the month of June,2013. my spouse`s H1B petition,2013 was under process during that time and now it is approved. She is presently not working as my son is just 11 months old and he has to be 16 months before he can go to the day care.

  1. Is it possible for my spouse to remain in H4 and start working from Jan,2014 without applying for CoS?

  2. Is it mandatory that she has apply for CoS right now otherwise her approved H1B would be cancelled?

  3. Is it possible she can transfer her unused H1B petition to a different employer and start working there?