Mistakes were made. I have some test devices in Jamf, deleted the wrong serial number (in a file for copy/paste).
Because of that, I was unable to retrieve the FileVault 2 recovery key to unlock the device to wipe it. Booting in to recovery wasn't giving me the option to log in as the user I had a password for.
** Commencing operation skid mark **
Thankfully, due to a series of fortunate events, I was able to find a way around. There's a blog post in this.
** phew **
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