I like
Nevaeh too as a gp. It is beautiful, especially when it's prn neh-VAY-uh. I suspect that's the correct prn since, as you say, that's how most people prn it.
Yeah, I guess it's a little tacky just because names spelled backwards or composed of random syllables are rather silly. I wouldn't say "all names were made up at some point"; most were derived from actual words in some language rather than being a word spelled backwards. I don't believe that Neveah is worse than
Nevaeh, either. I mean, if you can go as far as to spell a word backwards to get a name, why can't you change the spelling? Popular names pick up alternate spellings all the time.
Neaveh does look biblical to me, and no, it doesn't put me to mind of Nivea.
I don't know any Nevaehs nor how popular it is where I live.