I'm coming back to a comment I made before over the tool "search for undocumented characters".
It's better than it was, but still not perfect.
I haven't checked whether every single one works (there's a limit to how anally retentive one can be) but these ones definitely don't and they aren't particularly out of the way, especially the first, which is in fact used by about two hundred million people as their currency symbol. The œ is in common use in many countries and the trademark is used world wide.
The euro symbol € is not correctly identified and replaced by €
The oe ligature œ is "" "" and replaced by œ
and the Trademark symbol ™ isn't correctly identified and replaced either.
All the Best