Your list really isn’t that extensive for a [name]Berry[/name] list. It seems to me that you like fairly popular yet not trendy names. but your inclusion of [name]Callum[/name] and [name]Asher[/name] suggests you might be willing to look at some things outside of what could be a comfort zone.
Girls:
[name]Violet[/name] - I love [name]Violet[/name] and think it’s a really nice pairing with [name]Olivia[/name]. [name]Both[/name] are nature related but they aren’t too connected for it to be too obvious. I really like sib-sets that have a link of sorts so I think this is great. Also they are fairly similar in popularity level and that can be a plus.
[name]Emma[/name] - I like that both [name]Olivia[/name] and [name]Emma[/name] are used in famous English Literature (12th [name]Night[/name] and [name]Emma[/name]) which is a really subtle but fun connection especially if you and your husband are avid readers -> or you hope your girls will be. Again both are similar in popularity.
[name]Elise[/name] - I love [name]Elise[/name], it feels a bit short next to the 4 syllable [name]Olivia[/name]. [name]How[/name] about [name]Elisa[/name] or [name]Alisa[/name]? The extra -a almost ads a syllable and [name]Elise[/name] and [name]Olivia[/name] sound nice together.
[name]Chloe[/name], [name]Natalie[/name] and [name]Kate[/name] are nms.
Boys list-
[name]Jonah[/name] - I love this name. I feel like it’s underused. I don’t think I’ve ever meet a [name]Jonah[/name] (though plenty of [name]Jones[/name]’, [name]John[/name], ect.) It also goes nicely with [name]Olivia[/name] which I like. I also think that while it isn’t quite as popular as [name]Olivia[/name] it is definitely a well known name and easily recognizable. I also like that both names have o’s and a’s.
[name]Asher[/name] - I like [name]Asher[/name] as a name but I don’t think it’s as nice with [name]Olivia[/name]. If you don’t care about sib-set flow (and some don’t) I think this is a really great option.
[name]Noah[/name] - [name]Olivia[/name] and [name]Noah[/name] are great together. I like that both names have o’s and a’s.
[name]Callum[/name] and [name]Seth[/name] are nms.
Other names to consider my include: [name]Henry[/name], [name]Abel[/name], [name]Zachary[/name], [name]Ian[/name], [name]Viola[/name], [name]Iris[/name], and [name]Phoebe[/name].