Sorry, she qualifies as your dependent. You can leave her on your return and only need to fix (not amend) her rerturn. On her return she needs to check the box under My Info that she can be claimed as a dependent. Then she can efile. Oh, she fixed that and efiled ok? Then you don't have to do anything on your return or her return.
I don't know about the AOTC. @xmasbaby0
