(For my writing just in case you’re confused) Ok well, the way ive written them is, there are 6 siblings, and 4 have book names and 2 don’t. Should there be more of a trend? The book inspired names and the book they are from are:
[name_m]Atticus[/name_m]- To kill a mockingbird by [name_u]Harper[/name_u] [name_u]Lee[/name_u]
[name_f]Matilda[/name_f]- [name_f]Matilda[/name_f] by [name_m]Roald[/name_m] Dahl
[name_m]Peter[/name_m]- The chronicles of [name_f]Narnia[/name_f] by C.S. [name_m]Lewis[/name_m]
[name_f]Alice[/name_f]- [name_f]Alice[/name_f] in Wonderland by [name_m]Lewis[/name_m] [name_u]Carroll[/name_u].
The other two siblings are called [name_u]Kai[/name_u] (its Hawaiian for sea, and it was to honour someone) and [name_f]Cassia[/name_f] (It means [name_f]Cinnamon[/name_f] and she has exactly that colour eyes)
So is it too much? Are there any names you think would go better? I’m open to suggestions
([name_f]Edit[/name_f]: I’m mostly just asking for suggestions for [name_f]Cassia[/name_f] alternatives now, she is an 11 year old girl, her middle name is [name_f]Aelia[/name_f], she has dark brown hair and cinnamon brown eyes)
Personally, if I was writing a story I would keep the theme consistent. Parents who have an established “naming theme” are likely to continue that theme for all their kids e.g. the Duggars have 19 kids whose names all begin with J. I would maybe look for literary namesakes for [name_u]Kai[/name_u] and [name_f]Cassia[/name_f] (I’m sure about [name_f]Cassia[/name_f], but I do know that [name_u]Kai[/name_u] appears in [name_m]Hans[/name_m] [name_u]Christian[/name_u] [name_u]Anderson[/name_u]’s The [name_u]Snow[/name_u] [name_f]Queen[/name_f]).
[name_m]Ah[/name_m] thank you, the fact the theme continues a bit with [name_u]Kai[/name_u] helps
Some literally girl name suggestions
[name_f]Estella[/name_f] ([name_m]Charles[/name_m] Dickens Great Expectation)
[name_f]Josephine[/name_f] ([name_u]Jo[/name_u]) [name_m]Little[/name_m] Women
[name_f]Dixie[/name_f] or [name_f]Opal[/name_f] (Because of [name_u]Winn[/name_u] [name_f]Dixie[/name_f])
[name_f]Juliet[/name_f] (R&J)
[name_f]Mary[/name_f] (The [name_f]Secret[/name_f] Garden)
[name_f]Elizabeth[/name_f] (Pride & Prejudice)
[name_f]Scarlett[/name_f] (Gone with the Wind)
[name_f]Charlotte[/name_f] or [name_f]Fern[/name_f] ([name_f]Charlotte[/name_f]’s [name_m]Webb[/name_m])
[name_f]Meg[/name_f] ( A Wrinkle in Time)
[name_f]Madeline[/name_f] ([name_f]Madeline[/name_f])
[name_u]Leslie[/name_u] ([name_m]Bridge[/name_m] to Terabitia)
[name_f]Hope[/name_f] these help : )
[name_f]Estella[/name_f]- [name_f]Lovely[/name_f]
[name_f]Josephine[/name_f]-Cute!
Never read this and tryna stick to ones I know
[name_m]Ive[/name_m] got a character called [name_f]Juliet[/name_f] already
[name_f]Mary[/name_f]-Never really been a fan 
[name_f]Elizabeth[/name_f]- that could work
[name_f]Charlotte[/name_f] or fern-oooh interesting
[name_m]Ive[/name_m] not read the rest.
This was helpful thanks
If you want any more suggestions I would be happy to help : )
In fiction, naming themes are often fun and meaningful for the readers, but if you love the names “[name_u]Kai[/name_u]” and “[name_f]Cassia[/name_f],” there’s no reason you shouldn’t keep them, especially as [name_m]Peter[/name_m] and [name_f]Alice[/name_f] are common enough on their own that they might not only be associated with the books.
However, if you’re looking for literary names, I have a few suggestions that have strong associations for me.
[name_u]Abilene[/name_u]- a place name, but also the name of a character in The Miraculous [name_u]Journey[/name_u] of [name_m]Edward[/name_m] Tulane which is a children’s book that I think goes well with some of the books you’ve chosen; written for kids but beloved by adults.
[name_u]Anne[/name_u]- Simple, classic, [name_u]Anne[/name_u] of [name_u]Green[/name_u] Gables. [name_f]Blythe[/name_f]- [name_m]Gilbert[/name_m]’s last name, and eventually [name_u]Anne[/name_u]’s- is also a nice choice, or her friend’s name, [name_f]Diana[/name_f].
[name_f]Elizabeth[/name_f]- Simple and classic on its own, but can be associated with books such as Pride and Prejudice and [name_m]Little[/name_m] Women.
[name_m]Caspian[/name_m], [name_f]Lucy[/name_f]- The Chronicles of [name_f]Narnia[/name_f]
[name_f]Hermione[/name_f], [name_m]Albus[/name_m], [name_f]Ariana[/name_f], [name_f]Ginny[/name_f], [name_f]Molly[/name_f], [name_m]Fred[/name_m], [name_m]George[/name_m], [name_u]Dean[/name_u], [name_u]Percy[/name_u], [name_m]Seamus[/name_m], [name_u]James[/name_u], [name_m]Arthur[/name_m], [name_m]Cedric[/name_m], [name_m]Bill[/name_m], [name_u]Charlie[/name_u], [name_f]Lily[/name_f], [name_f]Sibyl[/name_f], [name_m]Harry[/name_m], [name_f]Luna[/name_f]- [name_m]Harry[/name_m] [name_m]Potter[/name_m].
[name_m]Oliver[/name_m]- [name_m]Oliver[/name_m] Twist
[name_m]Milo[/name_m]- The Phantom Tollbooth
[name_f]Charlotte[/name_f]- [name_f]Charlotte[/name_f]’s [name_m]Web[/name_m] and another name that is lovely and classic on its own.
[name_f]Arwen[/name_f], [name_f]Elinor[/name_f], [name_f]Eowyn[/name_f], [name_u]Sam[/name_u]- [name_m]Lord[/name_m] of the Rings.
[name_m]Hugo[/name_m]- The Invention of [name_m]Hugo[/name_m] Cabret, [name_m]Victor[/name_m] [name_m]Hugo[/name_m]
[name_m]Jonathan[/name_m]- [name_m]Jonathan[/name_m] Strange and Mr. Norrell
[name_f]Claudia[/name_f]- From the Mixed Up Files of Mrs. [name_m]Basil[/name_m] E. Frankweiler
[name_f]Guinevere[/name_f]- [name_m]King[/name_m] [name_m]Arthur[/name_m] and the Knights of the Round Table
[name_m]Theodore[/name_m], [name_u]Laurence[/name_u], [name_f]Amy[/name_f], [name_f]Margaret[/name_f]- [name_m]Little[/name_m] Women
[name_f]Juliet[/name_f]- [name_m]Romeo[/name_m] and [name_f]Juliet[/name_f]
[name_f]Jane[/name_f]- [name_f]Jane[/name_f] [name_f]Eyre[/name_f], [name_f]Jane[/name_f] [name_u]Austen[/name_u]
[name_u]Marian[/name_u]- as in Maid [name_u]Marian[/name_u] from the [name_u]Robin[/name_u] Hood stories.
[name_f]Ophelia[/name_f]- [name_m]Hamlet[/name_m]
[name_u]August[/name_u]- [name_f]Wonder[/name_f]
[name_m]Calvin[/name_m]- [name_m]Calvin[/name_m] and [name_m]Hobbes[/name_m]
[name_f]Penelope[/name_f]- The Odyssey (not that I like that book half as much as any of the others, but it’s still a nice name).
[name_m]Algernon[/name_m]- Flowers for [name_m]Algernon[/name_m]
[name_f]Imogene[/name_f]- [name_m]Fried[/name_m] [name_u]Green[/name_u] Tomatoes
[name_f]Madeline[/name_f]- From the children’s book series.
[name_u]Author[/name_u]’s names:
(W.H.) [name_u]Auden[/name_u]
([name_f]Jane[/name_f]) [name_u]Austen[/name_u]
([name_f]Maya[/name_f]) [name_f]Angelou[/name_f]
([name_m]Edgar[/name_m] [name_m]Allen[/name_m]) [name_u]Poe[/name_u]
[name_f]Sylvia[/name_f] (Plath)
[name_f]Beatrix[/name_f] ([name_m]Potter[/name_m])
[name_f]Agatha[/name_f] ([name_u]Christie[/name_u])
[name_f]Louisa[/name_f] [name_f]May[/name_f] [name_u]Alcott[/name_u] ([name_u]Alcott[/name_u] may work as a boy’s name)
[name_m]Dante[/name_m] (Alighieri)
[name_m]Nathaniel[/name_m] ([name_m]Hawthorne[/name_m])
[name_f]Hope[/name_f] this helps!
Wow!!! im actually drowning in suggestions 
At the moment im thinking [name_f]Elizabeth[/name_f], and a childhood and still friend of mine goes by [name_f]Ella[/name_f] to shake it up a bit.
[name_f]Charlotte[/name_f] is adorable too, ill have to look through the nicknames for that
All the little women sisters are on the shortlist
[name_f]Ophelia[/name_f] is a mournful name an I love it, just needs nicknames too
[name_f]Penelope[/name_f] is a funny coincidence, because I’m a huge classic nerd myself, and the Odyssey is easily one of my favourites. The obvious [name_u]Penny[/name_u] or perhaps more outlandish nicknames.
[name_f]Beatrix[/name_f] is lovely and I hadn’t considered authors.
Overall this had been really helpful!
The only [name_f]Ophelia[/name_f] I ever knew went by Opie! [name_f]Glad[/name_f] to help!
[name_f]Charlotte[/name_f] Nicknames - [name_f]Lottie[/name_f], [name_f]Char[/name_f], [name_u]Charlie[/name_u]
[name_f]Ophelia[/name_f] Nns - I love Opie, [name_f]Lia[/name_f], [name_u]Philly[/name_u], [name_u]Lee[/name_u]
[name_f]Penelope[/name_f] Nns - [name_u]Nelly[/name_u], [name_u]Penny[/name_u], [name_u]Pen[/name_u], [name_f]Elle[/name_f],
*[name_f]Elanor[/name_f]
[name_f]Cassia[/name_f] is a character in a trilogy called Matched. The series is written by [name_f]Ally[/name_f] [name_f]Condie[/name_f]. I just found it online, so I can’t say much about the series, but it gives a literary background for the name.