After substantially completing my 2015 return, I amended 2014. The Review section shows the old 2014 data. Is there a way to update the 2015 file with the new 2014 data?

The only possible way to update your 2015 taxes with the imported 2014 information, is to delete the .tax2015 file in the documents/turbotax directory, and start over. You have no other choice, as the import must be done first, before you can even start the 2015 return.