Can I backup or re-use my persistent data?

Yes, you can backup or re-use your persistent data. All you have to do is copying the casper-rw file (for Ubuntu and variants), live-rw file (for Debian and variants) or LiveOS\overlay-LABEL-XXXX file (for Fedora) when you are in Windows.

You can even put this file on another LinuxLive USB key with the same config to access your data.