One more aspect is that the (Linux) volume can be set to read-only which would stop malware from infecting the system.

We started working on an U2F implementation but it will take a few more months.

Nitrokey Storage can be preordered here and we plan it's shipment on 2nd May 2016.

For backup you should definitely backup your encryption keys (for email, SSH etc.). For the data files we don't have a backup solution yet. PrivacyBox would be an ideal solution but it's not clear when it will be available.

Fill in the blank.