Ok so suggestion #1 sounds made up to me but evidently it’s Hebrew for valley, I’m trying to like it because he really does. And #2 I like a lot but worried about popularity… here goes:
He’s vetoed all but 1 of my name choices at this point and that is [name]Dara[/name], which we still both really like thank goodness 
I have never heard of Denna. I don’t mind it though. [name]Ada[/name]/h I dislike.
Denna is…different. When I see it I think “[name]Denny[/name]'s” to be honest. I don’t care for [name]Adah[/name], but [name]Ada[/name] is beautiful. Good luck!
I love [name]Adah[/name]! [name]How[/name] will you be pronouncing it? [name]Adah[/name] is pronounced [name]Ah[/name]-dah, I believe, while [name]Ada[/name] is pronounced as Ay-dah.
I like [name]Ada[/name], feels simpler, clear & beautiful.
Denna is not for me. Like [name]Jenna[/name] but makes me think of [name]Dennis[/name]…like it’s someone’s feminization of [name]Dennis[/name]? It also makes me think den of _____. Like den of thieves.
I am not such fan of Denna, but I like both [name]Adah[/name] and [name]Dara[/name]. [name]Dara[/name] being my preference. Neither [name]Adah[/name] nor [name]Ada[/name] are extremely popular at the moment so I won’t worry too much about it (unless you personally know several little [name]Adah[/name]/[name]Ada[/name]'s)
Pronouncing it Ay-da… but it’s in the bible with an h so i think that’s where he’s getting the spelling. It makes no difference to me how we spell it honestly, I’m just worried it’ll be the next [name]Ava[/name].
I like Denna
I got to know Denna through a series of fantasy books I read, and there she was a very complex character in a quite mature setting. I’m not sure I would use it for my daughter though. It’s a very difficult character to explain, but she’s my main association to the name, so the two are very intertwined for me. The book is called '[name]Wizard[/name]‘s First [name]Rule[/name]’ by [name]Terry[/name] Goodkind, you could (should?) read about it somewhere online.
I also like [name]Adah[/name], but [name]Dara[/name] seems a little masculine to me for some reason. [name]Mara[/name] would be better.
He actually read the name in a book series so maybe it’s the same one… I think the book he’s reading now is called Name the Wind or something close to it. We don’t like [name]Mara[/name] though, it means bitter. [name]Dara[/name] is pronounced like [name]Sarah[/name] and means compassionate in Hebrew.
[name]Dara[/name] is so beautiful! I love its meaning too. Denna doesn’t look made up to me, but I don’t like the sound of it much. [name]Adah[/name] is nice, but you may encounter pronunciation issues. You’ve probably looked at all kinds of Hebrew names, but here are some others that I love:
[name]Havilah[/name]
Liat
[name]Yael[/name]
[name]Hazel[/name]
[name]Eliora[/name]
[name]Naava[/name]
[name]How[/name] do you pronounce Liat and [name]Naava[/name]? I think [name]Eliora[/name] is really pretty, and good nn potential too
If it’s the same book series, it’s probably ‘[name]Temple[/name] of the Winds’.
There’s another character there called [name]Cara[/name], it was always my favourite from the books 
I think [name]Dara[/name] reminds me of [name]Darragh[/name], an Irish boys name meaning ‘oak’. Pronounced almost the same.
[name]Mayim[/name], [name]Dinah[/name], Lior, [name]Aviva[/name], [name]Dalit[/name], [name]Hadassah[/name], Irit, [name]Nessa[/name], [name]Noa[/name], [name]Shiri[/name], [name]Shoshannah[/name], [name]Zakiah[/name], [name]Rivka[/name], [name]Mara[/name] and [name]Doveva[/name] are my favourite Hebrew names. And I have a soft spot for [name]Tamar[/name], the overlooked. 
Liat is pronounced [name]Lee[/name]-aht (aht sounding similar to aunt). I’m not sure about the pronunciation of [name]Naava[/name], but my guess is Nah-va with a soft a, sounding similar to “novel.”
Yes, I love [name]Eliora[/name]!
I love [name]Ada[/name]! (no H on the end).
I really like [name]Ada[/name]/[name]Adah[/name], though I’m biased, because it’s my grandmother’s name. I don’t think it’ll be the next [name]Ava[/name]…it doesn’t have the same image at all (names ending in “da” never seem to be massively popular).
I also like [name]Dara[/name] - very pretty! I’m not fond of Denna though (I prefer [name]Jenna[/name] or [name]Della[/name]).