I use this quite often and you can alter it as long as you change the group before hand

they are answering the questions as fill in the blank, ordering, essay etc.   Once it is graded they cannot go back in and change their answers (corrections) this is what I need them to be able to ...

When you go in to the assessment you want to edit, you must first select which group you want (upper right corner).  Then, you make your edits and save.  Now if she is in a group with other student...

I use an app called My Voice Recorder.  It is free.   I then Upload that file as a media file.  Hope that helps