Lauren,
In that custom python script you are referencing each of the selected features attributes should be printed.
It would look like this:
Layer Name
Field name Field value
Field name Field value
Field name Field value
..... ................
If you are not getting this then you have made a mistake or missed a step.
The Discussion James an I are having in this thread does not use that custom python script print service. I make edits to the Print widget in WAB Dev Edition to check for a specific graphics layer in the app and take that GLs specific attributes and add them to the print widgets cTextElements (custom text elements object). The names of those custom text elements match the names of the elements in my custom print layout template.