H4 COS and transfer possibilities


My wife was on H1-B (valid till sep 30th 2015, same as I-94) and she resigned on jan 2nd 2015 and her H4 with COS was filed and received by USCIS before last working day. Her previous emitters have not revoked her H1-B and her H4 is still in initial review. In this case, if she finds an employer it will be an H1-B transfer case taking the valid I-797 from either if the previous employers? What if her previous employer revokes the H1-B? Will there be any issues for H1-B transfer?