[name_m]Hi[/name_m] all 
I’m struggling a bit with a middle name for [name_f]Cleo[/name_f]. Last name will start with S, one syllable.
Her sister is [name_f]Ivy[/name_f] [name_f]Isobel[/name_f]
Thinking 2 or 3 syllables is best. Something well known, feminine…
So far in order of most preferred we have:
[name_f]Cleo[/name_f] [name_f]Charlotte[/name_f] S
[name_f]Cleo[/name_f] [name_f]Sophia[/name_f] S
I should add we haven’t tried to alliterate on purpose, its just coincidence that we like those names! Any thoughts on [name_f]Charlotte[/name_f] or [name_f]Sophia[/name_f]?
We did have and ruled out:
[name_f]Margaret[/name_f] (sounds to ‘hard’ with [name_f]Cleo[/name_f] to us)
Margeurite (feel like its trying a bit, personally, as we aren’t french, lol)
[name_f]Scarlett[/name_f] (just not sure? Too racy, flow not good?)
[name_f]Madeleine[/name_f] (its seems people can never agree on how it is pronounced, too confusing and we don’t want Mad-uh-line)
[name_f]Amelia[/name_f] (lovely! But someone we know and i just associate the name with her)
Thoughts on any of these or other middle names welcome… I feel like middle names shouldn’t be this hard! Thanks 
I don’t think pronouncing issues should be your problem when picking a middle name. It may not be used often, or when she’s older she can assert some independence by way of declaring an ‘official’ pronounciation. (All this to say I like [name_f]Cleo[/name_f] [name_f]Madeline[/name_f])
Of your two I prefer [name_f]Cleo[/name_f] [name_f]Charlotte[/name_f], and if you’re into alliteration, I’d suggest [name_f]Cleo[/name_f] [name_f]Cecilia[/name_f].
I like [name_f]Cleo[/name_f] [name_f]Charlotte[/name_f] from your list. Some suggestions:
[name_f]Cleo[/name_f] [name_f]Alexandra[/name_f]
[name_f]Cleo[/name_f] [name_f]Ariadne[/name_f]
[name_f]Cleo[/name_f] [name_f]Daphne[/name_f]
[name_f]Cleo[/name_f] Esmé
[name_f]Cleo[/name_f] [name_f]Isabel[/name_f]
[name_f]Cleo[/name_f] [name_f]Isadora[/name_f]/[name_f]Isidora[/name_f]
[name_f]Cleo[/name_f] [name_f]Madeline[/name_f]
[name_f]Cleo[/name_f] [name_f]Magdalen[/name_f]
[name_f]Cleo[/name_f] [name_f]Magdalena[/name_f]
[name_f]Cleo[/name_f] [name_f]Sylvia[/name_f]
[name_f]Cleo[/name_f] [name_f]Thisbe[/name_f]
My favorites are [name_f]Cleo[/name_f] [name_f]Alexandra[/name_f] and [name_f]Cleo[/name_f] [name_f]Thisbe[/name_f]. Good luck!
[name_f]Cleo[/name_f] [name_f]Charlotte[/name_f] and [name_f]Cleo[/name_f] [name_f]Sophia[/name_f] are lovely. Other possibiities…
[name_f]Cleo[/name_f] [name_f]Anneliese[/name_f]
[name_f]Cleo[/name_f] [name_f]Valentina[/name_f]
[name_f]Cleo[/name_f] [name_f]Francesca[/name_f]
[name_f]Cleo[/name_f] [name_f]Magnolia[/name_f]
Of your options, I prefer [name_f]Cleo[/name_f] [name_f]Charlotte[/name_f]… [name_f]Cleo[/name_f] and [name_f]Sophia[/name_f] are too similar in sound for my taste.
Other suggestions:
[name_f]Cleo[/name_f] [name_f]Vivienne[/name_f]
[name_f]Cleo[/name_f] [name_f]Rhiannon[/name_f]
[name_f]Cleo[/name_f] [name_f]Louise[/name_f]
[name_f]Cleo[/name_f] [name_f]Adeline[/name_f]
[name_f]Ivy[/name_f] [name_f]Isobel[/name_f] {and} [name_f]Cleo[/name_f] [name_f]Catherine[/name_f]
I kind of like that [name_f]Cleo[/name_f] [name_f]Charlotte[/name_f] would match the alliteration of your older daughter’s name.
[name_f]Cleo[/name_f] is one of my all-time favorites—my usual combo for it is [name_f]Cleo[/name_f] [name_f]Iphigenia[/name_f] (a bit on the wild side.)
Other ideas:
[name_f]Cleo[/name_f] [name_f]Adele[/name_f]
[name_f]Cleo[/name_f] [name_f]Amaya[/name_f]
[name_f]Cleo[/name_f] [name_f]Aurora[/name_f]
[name_f]Cleo[/name_f] [name_f]Camille[/name_f]
[name_f]Cleo[/name_f] [name_f]Corinne[/name_f]
[name_f]Cleo[/name_f] [name_f]Eliza[/name_f]
[name_f]Cleo[/name_f] [name_f]Emilia[/name_f] (too close to [name_f]Amelia[/name_f]?)
[name_f]Cleo[/name_f] [name_f]Emmeline[/name_f]
[name_f]Cleo[/name_f] [name_f]Fiona[/name_f]
[name_f]Cleo[/name_f] [name_f]Josephine[/name_f]
[name_f]Cleo[/name_f] [name_f]Juliet[/name_f]
[name_f]Cleo[/name_f] [name_f]Lucia[/name_f]
[name_f]Cleo[/name_f] [name_f]Seraphine[/name_f]
[name_f]Cleo[/name_f] [name_f]Susanna[/name_f]
[name_f]Cleo[/name_f] [name_f]Vanessa[/name_f]
Sorry for any repeats!
[name_f]Cleo[/name_f] [name_u]Valentine[/name_u] (I personally love this).
[name_f]Cleo[/name_f] [name_f]Isadora[/name_f]
[name_f]Cleo[/name_f] [name_f]Aurelia[/name_f] (Also love)
[name_f]Cleo[/name_f] [name_f]Amelie[/name_f]
[name_f]Cleo[/name_f] [name_f]Lucia[/name_f]
[name_f]Cleo[/name_f] [name_f]Cassia[/name_f] (pronounced with three syllables)
[name_f]Cleo[/name_f] [name_f]Violet[/name_f]
[name_f]Cleo[/name_f] [name_f]Magnolia[/name_f] (not sure if it’s your style but it sounds lovely)
[name_f]Cleo[/name_f] [name_f]Clementine[/name_f]
[name_f]Cleo[/name_f] [name_f]Eleanor/name_f
[name_f]Cleo[/name_f] [name_f]Leonora[/name_f]
Cleo Olivia
Cleo Livia
Cleo Helena
Cleo Sienna
Cleo Magdalena
Cleo Rowena
Cleo Ramona
Cleo Iona
Cleo Evelia
Cleo Xanthippe
[name_f]Cleo[/name_f] [name_f]Marigold[/name_f]
[name_f]Cleo[/name_f] [name_u]Evelyn[/name_u]
[name_f]Cleo[/name_f] [name_f]Jessamine[/name_f]
[name_f]Cleo[/name_f] [name_f]Felicia[/name_f]
[name_f]Cleo[/name_f] [name_f]Jillian[/name_f]
[name_f]Cleo[/name_f] [name_f]Miranda[/name_f]
[name_f]Cleo[/name_f] [name_f]Michaela[/name_f]
[name_f]Cleo[/name_f] [name_f]Adele[/name_f]
[name_f]Cleo[/name_f] [name_f]Elena[/name_f]
[name_f]Cleo[/name_f] [name_f]Adelaide[/name_f]
[name_f]Cleo[/name_f] [name_f]Melody[/name_f]
[name_f]Cleo[/name_f] [name_f]Mariel[/name_f]
Oh some very cool names here, even if thet are ones we wouldn’t use!
Yeah i think we will scrap [name_f]Sophia[/name_f] as a possible middle, it does flow a bit samey, which i was wondering about with it.
I do like [name_f]Catherine[/name_f] but it doesn’t work with our last name unfortunately. [name_f]Emelia[/name_f] is a possiblity.
I’m still liking on [name_f]Charlotte[/name_f], but does [name_f]Cleo[/name_f] [name_f]Charlotte[/name_f] really flow that well? Or does [name_f]Cleo[/name_f] [name_f]Madeleine[/name_f] sound better? I’m on the fence with those
[name_f]Ivy[/name_f] [name_f]Isobel[/name_f] S with:
[name_f]Cleo[/name_f] [name_f]Charlotte[/name_f] S
[name_f]Cleo[/name_f] [name_f]Madeleine[/name_f] S
[name_f]Cleo[/name_f] [name_f]Emilia/Emelia[/name_f] S
I think [name_f]Cleo[/name_f] [name_f]Madeline[/name_f] flows a bit better than [name_f]Cleo[/name_f] [name_f]Charlotte[/name_f].