I think it works just fine with older siblings. It’s not what I’d necessarily think of as a sibling name but it’s gentle in sound and not dissimilar in popularity.
[name_f][/name_f]I wouldn’t limit your options based on the letter pattern. It makes the task a lot harder without much gain. I don’t think anyone would noticed unless they were looking really closely, any even then, it’s just a coincidence.
[name_f][/name_f]It’s good to have a name you can agree on --even if it’s just one. Nice to have a few more options too. A few ideas:
[name_f][/name_f][name_m]Aaron[/name_m] [name_f][/name_f]- high mountain, exalted, enlightened
[name_f][/name_f][name_m]Ezra[/name_m] [name_f][/name_f]- helper
[name_f][/name_f][name_m]Josiah[/name_m] [name_f][/name_f]- [name_m]God[/name_m] supports, heals
[name_f][/name_f][name_m]Abel[/name_m] [name_f][/name_f]- breath
[name_f][/name_f][name_m]Casper[/name_m] [name_f][/name_f]- bringer of treasure
[name_f][/name_f][name_m]Ethan[/name_m] [name_f][/name_f]- strong, enduring, firm
[name_f][/name_f][name_m]Jonathan[/name_m] [name_f][/name_f]- [name_m]God[/name_m] had given
[name_f][/name_f][name_m]Hugo[/name_m] [name_f][/name_f]- bright in mind and spirit
[name_f][/name_f][name_m]Reuben[/name_m] [name_f][/name_f]- behold, a son
[name_f][/name_f][name_m]Ezekiel[/name_m] [name_f][/name_f]- [name_m]God[/name_m] is strong, [name_m]God[/name_m] strengthens