H1b visa denied,reappealing through i290b


I have 3 questions.Appreciate you answering them.

1)I work for Company A on H1B and my wife’s H4 was approved based on this Company A’s petition with I-94 valid till september 2015.I am switching my job and moving onto Company B which has my H1B approved and valid till 2016.They did not process my wife’s H4 and said that her H4 which was filed previously is still valid even if make a switch employer and USCIS prefers not to issue many I-94’,so he suggested us to have the same h4 till 2015 and then they will extend her H4 at end of 2015.Is it legal to stay on an H4 which was filed based on previous employers H1B petition?

2)My Wife’s H1B got denied.Her H4 is valid till end of 2015.Is she in legal status inspite of her H1B denial.I suppose she is legal to stay,but need a confirmation.Or do i need to ile any COS again?

3)We are planning to appeal against the H1B denial for my wife through I290B.I heard that it takes almost an year to get resolved.When the notice of appeal is in progress,can she travel outside the country?Does travelling abroad abondon that application status?