Mia, Oliver, and ???

Name Advice
1

We are expecting our DD in a few months, and she will be named [name]Mia[/name]. We had [name]Oliver[/name] chosen if she was a boy. So my question is, what you name a brother and sister to [name]Mia[/name] and [name]Oliver[/name]?

[name]Mia[/name], [name]Oliver[/name], and (girl)
[name]Mia[/name], [name]Oliver[/name], and (boy)

2

The first names that I thought of were…
[name]Mia[/name], [name]Oliver[/name] and [name]Zoe[/name]
[name]Mia[/name], [name]Oliver[/name] and [name]Sebastian[/name]