My husband and I have been stuck on these three names for months and just keep going around in circles.
Seraphina
Celeste
Ophelia
Brother names are Casper and Felix.
Please let me know your favorite and whether you dislike/hate any of these names! I won’t think you’re rude. If people have strong negative reactions to any of them, I’d rather know now!
Thank you :))
All three are beautiful, but I love [name_f]Ophelia[/name_f], and I think it’s perfect in your set!
First of all congratulations!!! 
I’d personally rank them
[name_f]Ophelia[/name_f] & [name_f]Seraphina[/name_f] are just stunning. I’ve had both on my list at one point! I think [name_f]Ophelia[/name_f] would probably fit the best with your boys names in my opinion (I love your boys names so much by the way!)
I’m not the biggest [name_f]Celeste[/name_f] fan as I just can’t seem to get past the word it rhymes with 
All 3 are lovely names, CeIeste is my favourite with [name_f]Seraphina[/name_f] being a close second. As a sibset I think [name_f]Seraphina[/name_f] or [name_f]Ophelia[/name_f] fit best, [name_m]Casper[/name_m] and [name_f]Celeste[/name_f] would share an initial, not that big of a deal to me, but [name_m]Felix[/name_m] might possibly feel left out (?) Honestly, you can’t go wrong with these names 
[name_u]Love[/name_u] [name_f]Ophelia[/name_f] the with [name_m]Casper[/name_m] and [name_m]Felix[/name_m]
[name_f]Seraphina[/name_f] is my favorite of the three, but I think [name_f]Ophelia[/name_f] fits best with your boys.
i adore seraphina w casper & felix!! celeste would come as a close second
[name_f]Seraphina[/name_f] gets my vote! Not only is it beautiful, but it goes great with [name_m]Casper[/name_m] and [name_m]Felix[/name_m]!
I think Seraphina goes best with your set!
They are all pretty names. [name_f]My[/name_f] favourite is [name_f]Ophelia[/name_f] and I think this sounds lovely as a sister to [name_m]Casper[/name_m] and [name_m]Felix[/name_m].
[name_m]Casper[/name_m] & [name_m]Felix[/name_m] are so perfect together! I really love [name_f]Seraphina[/name_f] with them! [name_m]Casper[/name_m], [name_m]Felix[/name_m], and [name_f]Seraphina[/name_f] make such a beautiful, magical sibset!
I also really like Ophelia!!
I love your sons’ names! [name_f]Celeste[/name_f] is my favorite with them. It’s an understated, beautiful, strong name that will age wonderfully.
I love [name_f]Celeste[/name_f] in general, and I love it with your boys’ names! That’s definitely my favorite from your list. I generally prefer to avoid repeated initials within a sibset, but it doesn’t bother me as much here because a) the “C” makes a different sound in [name_m]Casper[/name_m] and [name_f]Celeste[/name_f] and b) I just feel strongly enough about preferring it!
[name_f]Lovely[/name_f] list! [name_f]Ophelia[/name_f] sounds gorgeous with your son’s names but the name itself is also very similar to [name_m]Felix[/name_m] so that’s something to consider. Still love it though! [name_f]My[/name_f] second favorite is [name_f]Seraphina[/name_f]. 
i love all of of these names, but my favourite (both in general and with your sibset) is the perfect ophelia!
I love [name_f]Ophelia[/name_f], it’s very elegant. I like [name_f]Seraphina[/name_f] but it’s a little to frilly compared to [name_m]Casper[/name_m] and [name_m]Felix[/name_m].
[name_m]Hi[/name_m] there.
[name_m]Casper[/name_m] & [name_m]Felix[/name_m] are cute!
Here are my thoughts on a little sister-
Seraphina-I don’t hate it. But I don’t like it for some reason. Most people seem to. It’s just a little clunky in my opinion.
Celeste-Ooh, very pretty. It’s elegant & well…celestial! It’s well known but unique & grows up well. And it goes nicely w/big brothers’ names.
Ophelia-Another name that most people seem to like & I just can’t get into. It feels kind of dark & evil to me.
[name_f]Hope[/name_f] this helps. 
Definitely Ophelia,I really love that name and I think that it matches [name_m]Casper[/name_m] and [name_m]Felix[/name_m] best,but I find [name_f]Celeste[/name_f] is cute too
[name_f]Celeste[/name_f] is nice I love [name_f]Seraphina[/name_f] but it’s too long for me
I like [name_f]Celeste[/name_f] best here. It has a more distinct sound next to her brothers.
[name_f]Ophelia[/name_f] and [name_f]Seraphina[/name_f] both have that prominent F sound which is similar to Felix…
When said together-makes them harder to say/yell (ha) IMO.
But all are lovely names! Good luck