You have a great shortlist and I honestly don’t think you could go wrong with any of them!
[name_f][/name_f]I will say that [name_f]Ruby[/name_f] (and especially [name_f]Nora[/name_f] and [name_f]Hazel[/name_f], if you’re still considering them) are actually quite popular in the US at this point, moreso than [name_m]Maxwell[/name_m], so they may be more common than you’re looking for.
[name_f][/name_f]Some more suggestions…
[name_f][/name_f][name_f]Olive[/name_f]
[name_f][/name_f][name_f]Ruth[/name_f]
[name_f][/name_f][name_f]Mabel[/name_f] (maybe too matchy with Maxwell)
[name_f][/name_f][name_f]Diana[/name_f]
[name_f][/name_f][name_f]Greta[/name_f]
[name_f][/name_f][name_f]Eve[/name_f]
[name_f][/name_f][name_f]Heidi[/name_f]
[name_f][/name_f][name_f]Matilda[/name_f]
[name_f][/name_f][name_f]Etta[/name_f]
[name_f][/name_f][name_m]Ada[/name_m]
[name_f][/name_f][name_f]Louisa[/name_f]
[name_f][/name_f][name_f]Daphne[/name_f]
[name_f][/name_f][name_f]Harriet[/name_f]
[name_f][/name_f][name_f]Opal[/name_f]
[name_f][/name_f][name_f]Pearl[/name_f]
[name_f][/name_f][name_f]Greer[/name_f]
[name_f][/name_f][name_f]Cora[/name_f]