i lurked for a while hoping to find timely updates on the tv show production, but i saw this and i must try to clear this misunderstanding.
robert jordan used a lot of real world mythology as inspiration for names, among other things. the idea is that the world of the wheel of time is both a distant past and a distant future of our world, and some of our myths are those stories twisted by time and retelling until they were unrecognizable.
for example, the dark one's name is shai'tan, which is the name of the devil according to islam - itself derived from the satan of christian/judaic tradition. rand al'thor is meant to evoke both the thor of nordic mythology, and king arthur, while perrin comes from the ancient slavic god perun, that was incorporated in christian tradition as saint elyas; there is an elyas who will be important for perrin. and there are several points of contact between those characters and the mythological characters who influenced their names. the trolloc are troll-orcs.
there are long essays showing points of contact between the characters and places of the wheel of time and mythology from all around the world, from the monotheistic religions to ancient nordic mythology, to induism, the cycle of king arthur, and many others. those are intentional.
so, if you are afraid that the wheel of time is a book on demonology filled with subliminal messages to worship the devil, that's utterly ridiculous. and by the way, subliminal messages don't work that way. some things, though, are intentionally meant to evoke things from real world mythologym, or hystory.
that said, is emond/demon and jehannah/gehenna a relevant connection? the names may be partially inspired, certainly, but there is no further connection. emond field has nothing to do with demons, except maybe the trollocs that come to attack it, and jehannah isn't ever even seen throughout the whole 14 books.