Actually, I've done volumes of reading since I posted that question.
First of all, TC cannot
encrypt an ReFS formatted drive.
Second of all ReFS definitely cannot
be used to format an external (USB) drive.
Thanks for posting the link. Actually there is major tonnage of info about ReFS on the net - to be found via Google.
As "For those not aware of what ReFS is", I can only say that it's just a matter of time before all sophisticated computer users know about ReFS. In the same way that NTFS replaced (for the most part) FAT, ReFS will be replacing NTFS.
This article is succinct and very much to the point: Q: What features does NTFS support that ReFS does not support? | Windows Server 2012 content from Windows IT Pro