I think all of your frontrunners are perfect options for Emma’s brother. I know that’s not super helpful.
[name_f][/name_f]Perhaps more suggestions?:
[name_f][/name_f][name_m]Carter[/name_m]
[name_f][/name_f][name_m]Eric[/name_m]
[name_f][/name_f][name_m]Evan[/name_m]
[name_f][/name_f][name_m]Everett[/name_m]
[name_f][/name_f][name_m]Louis[/name_m]
[name_f][/name_f][name_m]Oscar[/name_m]
[name_f][/name_f][name_m]Owen[/name_m]
[name_f][/name_f][name_m]Robert[/name_m]
[name_f][/name_f][name_m]William[/name_m]