It worked in this scene I made. You could use a regex with the match command to find the suffix and convert that to an int value to use in setting keyframes. I went with the first keyframe on the dummy camera since it was a sure shot without knowing the naming conventions (which also gives it the flexibility to work with any selection of transforms).

Made with Maya 2017
copyCamKeys_test_01
To reset and test for yourself, delete the keyframes on camera1, select cameras 2 through 14 then run the script.