How to backup applications' data from second or subsequent user of a currently non-rooted device?

Question

Primary question: given a non-rooted 4.2.2 device which has second user added and used for awhile, is there any way to backup or otherwise safe the application's data of that second (or third etc.) user? I would like to have backup of application's data only, like what produced by adb backup. Full backup is fine if you also include information on how to eventually extract the application's data. Software procedure that destroy the system is acceptable as long as the application's data of second user's can be saved, so rooting the device is fine if you let me know how to do it with the application's data of second user intact.

I have try backing it up using adb backup but I don't see any data from the second user in it.

Additional question: I also want to restore a backup into second user of another device. It seems rooting the device will be the best way, right? Or there is another way?

More case specific information: I have a non-rooted Asus MeMO Pad HD 7 running 4.2.2 with second user setup and used, but now have cracked screen and other issues. I have replacement device a Dell Venue 7 running 4.4.3, but because of different capability, I want to setup the later device with the 2 accounts swapped, i.e. 1st account of the MeMO Pad HD 7 will become second user in the Venue 7 and vice versa.

Answer 1

I use Helium on a non-rooted Nexus 7 (2013) to backup my app data (but not the apps). I have only one user account but since that app data is user-specific, is contained in my user area, and the backup is placed in my user area, I'd be surprised if Helium would have any trouble backing-up each account separately. I have not had occasion to restore a user's data from a Helium backup, so be I can't vouch for that process.