I did a little poking around in your GE name file. The diacritical E and umlouted o are not valid in UTF-8. That is the reason that the file won't load in an xml editor or in a UTF-8 only editor. It is also inconsistent with your stated standards for the file in your HELP - all the files need to be UTF-8. I changed the characters to an e and an o and removed the one single quote and that worked.
https://www.liquid-technologies.com/XML/EscapingData.aspx
I rather suspect failure to escape the single quote may be what is hosing up the Unit DB. I suspect when you make the copy of the Unit DB, you are not processing the single quote properly. This could cause all kinds of issues.
The same issue with single quotes is present in some of your other files like the Localization XML. I went ahead and escaped all the single quotes per the standard and you are probably using a standard XML parser because all the single quotes appear like they should in the help and tool tip texts. I not sure why that was not giving you a problem with the game - maybe it is! In any case it appears that the escape sequences are being processed as they should be.