Awe, I love [name]Charles[/name]/[name]Charlie[/name]!
If you’re using [name]Charles[/name], I think you can still use your girls’ names, unless you’re trying to stay away from nicknames that end in the “ee” sound.
For boys, thoughts on these?
[name]Luke[/name] and [name]Charlie[/name]: I think it definitely works…
[name]West[/name] and [name]Charlie[/name]: I’d stick with classic/vintage names with [name]Charles[/name]/[name]Charlie[/name]. I know it doesn’t fit into those categories, but what about [name]Weston[/name], nn [name]West[/name]?
[name]Alec[/name] and [name]Charlie[/name]: Would he be [name]Alexander[/name], nn [name]Alec[/name]? I think that’s great with [name]Charles[/name]/[name]Charlie[/name]!
Girls?
[name]Caroline[/name] and [name]Charlie[/name]: While I love [name]Caroline[/name], it (along with [name]Charlotte[/name] and others), is the feminine of [name]Charles[/name], so I’d stay away from it. 
[name]Alden[/name] and [name]Charlie[/name]: It doesn’t work for me, plus I thought it was a boys’ name. (I’m thinking of Reverend [name]Alden[/name] from [name]Little[/name] House…)
[name]Charlie[/name] and [name]Claire[/name]: I think this is cute!
[name]Charlie[/name] and [name]Elliott[/name]: Not unless you want everyone to think you’ve got two boys!
As [name]Charlie[/name] can also be a girls’ nickname for [name]Charlotte[/name], I’d personally avoid gender amiguity!
[name]Charles[/name]/[name]Charlie[/name] and:
[name]Alice[/name]
[name]Amelia[/name] (nn [name]Mia[/name], to avoid [name]Millie[/name], which has the ie ending)
[name]Beatrix[/name] (I think [name]Charlie[/name] and [name]Bea[/name] is cute!)
[name]Blythe[/name]
[name]Clementine[/name] (instead of [name]Caroline[/name])
[name]Clara[/name]
[name]Emmeline[/name]
[name]Eliza[/name]
[name]Eloise[/name] (nn [name]Lulu[/name])
[name]Fiona[/name]
[name]Genevieve[/name]
[name]Hope[/name]
[name]Iris[/name]
[name]Juliet[/name]
[name]Lila[/name]
[name]Louisa[/name] (nn [name]Lulu[/name])
[name]Mae[/name]
[name]Rose[/name]
[name]Tess[/name]/[name]Tessa[/name]
[name]Oliver[/name]
[name]Edward[/name]
[name]Elias[/name]
[name]Finnian[/name]
[name]Harrison[/name]
[name]Henry[/name]
[name]Milo[/name]
[name]Miles[/name]
Are you sticking with [name]Charles[/name] [name]Everett[/name]? I think it’s beyond awesome!