What not to do: reset your password before you change/setup your keyboard locale, use punctuation characters in your new password, and then change the locale. Yeah, that’s not going to work. Now I don’t know where some of the characters moved to 🙂
I’m going to leave this post right here for future reference.
Update 2/3/16: after I edit the cmdline.txt and booted to a shell, passwd gave me this error:
passwd: Authentication token manipulation error
passwd: password unchanged
Further down the post, this recommendation to remount / solved my issue:
mount -rw -o remount /
Then I did passwd and the change worked this time.