[name]Charlotte[/name], [name]Matilda[/name] and [name]June[/name] sounds like an interesting sibset and is not completely discordant. However, the thing that strikes me is that [name]June[/name] does seem a bit insubstantial next to [name]Charlotte[/name] and [name]Matilda[/name]. [name]Charlotte[/name] and Matilda are visually and verbally longer, and are, quite literally, regal names. If I were you, I’d go with a classic name that has just as much weight behind it. [name]Elizabeth[/name], [name]Helena[/name], [name]Katherine[/name], [name]Victoria[/name], [name]Sophia[/name], [name]Isabel[/name], and [name]Eleanor[/name] are all obvious choices, but is seems that although you like classic names, you might want something just a bit off the current trend. [name]How[/name] about [name]Alice[/name], [name]Josephine[/name], [name]Guinevere[/name], [name]Julia[/name], [name]Portia[/name], [name]Juliet[/name], [name]Veronica[/name], [name]Adela[/name], [name]Phillipa[/name], [name]Cordelia[/name], [name]Antonia[/name], [name]Louisa[/name], [name]Beatrice[/name], [name]Rowena[/name], [name]Claudia[/name], [name]Clara[/name], [name]Penelope[/name], or [name]Emmeline[/name]?
[name]Arthur[/name] seems like a very good choice for a brother, and I love it. [name]Oscar[/name] is indeed a classic name, but personally I can never think past [name]Oscar[/name] the Grouch and [name]Oscar[/name] [name]Madison[/name]. Other boy suggestions: [name]Edmund[/name], [name]Edward[/name], [name]Geoffrey[/name], [name]Philip[/name], [name]Stephen[/name], [name]Peter[/name], [name]Paul[/name], [name]Gregory[/name], [name]Linus[/name], [name]Frederick[/name], [name]Oliver[/name], [name]Leo[/name], [name]Julian[/name], or [name]Sebastian[/name]?
Good luck. You have great taste in names, so you are sure to make a wonderful choice!