[name_f]Delphine[/name_f]- I love that it’s unique but recognizable, and the nickname [name_u]Del[/name_u] is so cute.
[name_f]Isabella[/name_f]- Shortened to [name_f]Bella[/name_f], I’ve loved this name for years but many people are tired of hearing it 
[name_f]Charlotte[/name_f]- Classic, feminine but still strong.
[name_f]Penelope[/name_f]- Namesake name, shortened to [name_f]Nel[/name_f]. Not sure if I love love it yet.
Thoughts?
Isabella nn [name_f]Bella[/name_f] 
I adore these names!
[name_f]Delphine[/name_f] is definitely the rarest, so if you’re going for that, I like [name_f]Delphine[/name_f] nn [name_u]Del[/name_u] a lot!
[name_f]Isabella[/name_f] is my least favorite just bc it’s popular, but still very pretty.
[name_f]Charlotte[/name_f] is, like, my favorite name of all time, so obviously it’s got my vote. [name_f]Do[/name_f] you like [name_u]Charlie[/name_u], [name_f]Lottie[/name_f], [name_u]Coco[/name_u], or [name_f]Lola[/name_f] as nicknames?
[name_f]Penelope[/name_f] is very pretty, and still pretty underused where I am. Extra points for it being a namesake. It makes sense that you aren’t obsessed with it though, maybe with [name_u]Penny[/name_u] as a nn?
All of them are soo cute, I honestly don’t think you can go wrong!!
Delphine is my favourite, followed by [name_f]Penelope[/name_f]. [name_f]Charlotte[/name_f] is nice, too. I’m not personally a fan of [name_f]Isabella[/name_f].
It sounds like [name_f]Isabella[/name_f] is your favourite, though, so I wouldn’t let other people’s opinions (like being tired of hearing it) sway you from using it. Your the one that’ll be saying it on a daily basis.
My personal favorite from your list is [name_f]Charlotte[/name_f]! However, I don’t think you can go wrong with any of them.
Delphine is my favorite by far!
Delphine - Absolutely exquisite!
Isabella - Too popular, and kind of annoying.
Charlotte - Getting more common that preferable.
Penelope - It’s okay.
Hope this helps! 
Delphine! I adore it, especially with [name_f]Delphi[/name_f] as a nn…
My fav names right now are Charlotte and Lily, but Delphine is sooooo exquisite! Della or Delphi are adorable nicknames as well. But Delphine does make me think of “dolphin“ slightly, yet it is still elegant and rare and wonderful nonetheless. Sure, Delphine might evoke more extreme reactions than your other names, but if you love it, you should go for it 
Also, Anne with an E was my first introduction to this name, so that’s a positive association!!
As for Penelope, I’ve unfortunately never been a fan. I understand its appeal, but it sounds like someone has a pinched nose when they say it, so that turns me off. To be fair, Penelope has striking Ancient Greek history behind it and it is well-loved by many
Isabella is fine and mostly not controversial, just not to my taste as much. Bella is a nice nickname and has become ubiquitous in our culture, which means there’s not a lot of risk involved🥰
Charlotte is my favorite, then [name_f]Penelope[/name_f]! I don’t really like the other two very much.
Isabella or [name_f]Charlotte[/name_f]- timeless classics. Personally not a fan of [name_f]Delphine[/name_f] and can’t stand [name_f]Penelope[/name_f] 
especially after I heard someone mispronounce it as [name_u]Penny[/name_u] Loop!
I do love the [name_f]Nel[/name_f] nn though- could you get [name_f]Nel[/name_f] from another name that would still honour the person? Maybe it’s too much of a stretch
Delphine! So gorgeous
I like [name_f]Delphine[/name_f]. You could call her [name_u]Dell[/name_u] or [name_f]Della[/name_f].
Delphine! All the way.
Oooh, so hard! [name_f]Isabella[/name_f] is so tempting since [name_f]Isabelle[/name_f] is my favorite girls’ name, myself.
I guess it would come down to nicknames–I love [name_f]Della[/name_f] for [name_f]Delphine[/name_f], [name_f]Lottie[/name_f] for [name_f]Charlotte[/name_f], [name_f]Poppy[/name_f] for [name_f]Penelope[/name_f], but am a bit picky as far as nicknames go with some of these, and that might sway me in a particular direction.
I think for now, in general, I’d say [name_f]Charlotte[/name_f]’s my favorite, although [name_f]Isabella[/name_f] is my safe answer since I know I love [name_f]Bella[/name_f]. 
I would say I love [name_f]Charlotte[/name_f] more than [name_f]Isabella[/name_f], but I like [name_f]Isabelle[/name_f] more than [name_f]Charlotte[/name_f], if that makes sense.
Good luck!
love [name_f]Delphine[/name_f] !
It would be [name_f]Delphine[/name_f] hands down if you know that the child will never ever want to live in a [name_m]German[/name_m] speaking country - pronounced exactly the same as the [name_m]German[/name_m] word for dolphin. Otherwise despite the popularity, [name_f]Isabella[/name_f] over [name_f]Charlotte[/name_f] and [name_f]Penelope[/name_f] any day.
Delphine sound a perfect
Delphine is perfection!
I love [name_f]Penelope[/name_f], NN [name_f]Nel[/name_f], that’s really great. That it’s a namesake makes it even better, too!