Backup is working fine from KODI 16 to 17.
There are some differences with the video and audio libraries,
but after you upgraded to 17 and restore your backup files,
KODI will automatically create new library files out of your old ones on the next boot.
So your steps will be:
On KODI 16 - backup your stuff.
Go to Backup addon settings and make sure this is selected:

(in your case, including thumbnails)
If you use a specific playercorefactory.xml you have to change it,
since" DVDplayer" from KODI 16 is now "VideoPlayer" in Kodi 17.
So open playercorefactory.xml on your pc and manually change every instance of DVDplayer to VideoPlayer.
(the file is at YEARMONTHDAYTIME/userdata)
Install latest Kodi 17 from here:
http://mirrors.kodi.tv/releases/android/arm/
Start Kodi 17, let it do its updates.
Disable Joystick Support in Kodi 17 to make sure your remote keep sworking:
Add-ons / My add-ons / Peripheral libraries / Joystick Support / Disable
Install Backup addon, restore files, using same settings as before.
On KODI home screen, hit "Back" on remote, chose "Exit" to close down KODI completely.
Restart KODI.
It will transfer Jarvis libraries to make them Krypton compatible.
Done.