I have to say that I think [name]Ava[/name] would be perfect with your other kids’ names!
I vote [name]Ava[/name] or [name]Lilly[/name].
[name]Halle[/name] for me, of your choices. I wouldn’t spell it any other way, either. I like [name]Holly[/name] too.
[name]Ava[/name] has a classier effect to me than [name]Avery[/name], and I don’t even like [name]Ava[/name] very much. I think [name]Eve[/name], however, sounds sleeker than [name]Ava[/name].
Other options:
[name]Amy[/name] - not trending upward, -y ending, not masculine, not especially cutesy, classic history.
[name]Aviva[/name] - pronounced ah-vee-va, less common than either [name]Ava[/name] or [name]Avery[/name], hardly masculine.
[name]Molly[/name], [name]Tilly[/name], [name]Polly[/name], [name]Millie[/name] - Two l’s, -y ending.
[name]Lillian[/name], [name]Lily[/name]/[name]Lilly[/name], [name]Lilibet[/name] - 2-3 l’s per name. I rather like [name]Lily[/name], nevermind its popularity.
The other option could be one of the -rita ending names, then [name]Rose[/name] as a middle, like [name]Sarita[/name] [name]Rose[/name]?