they are only two counties with a Hungarian majority. Also, only because historically Hungarians conquered Transylvania, there is no need for signs to be on Hungarian, because it isn't a regional language or state language. That's as if you said that in Poland signs should be written on Russian and German. Or as if that signs in Greece should be on Turkish too. Its just nonsense.
No, historically they belong to Romania. At some point they were part of the Austro-Hungarian empire, which doesn’t exist anymore. And what happened in WW2, when Hungary tried to take “back” Transylvania, cannot be taken into account.
Thanks.