Max.well is a handsome name! Not a huge fan of [name_m]Murphy[/name_m] [name_m]Campbell[/name_m], I confess.
[name_f][/name_f]For Emmy/Emmie, I adore [name_f]Emmeline[/name_f] with big bro’s name!
[name_f][/name_f]From your girl’s list, [name_f]Emmeline[/name_f] [name_f]Cleo[/name_f] would be SO gorgeous on its own and with big bro’s name IMO 
For little brothers:
[name_f][/name_f][name_m]Graham[/name_m] [name_m]Osborne[/name_m]
[name_f][/name_f][name_m]Julius[/name_m] [name_m]Salvatore[/name_m]
[name_f][/name_f][name_m]Lionel[/name_m] [name_m]Robert[/name_m]
For little sisters (other than [name_f]Emmeline[/name_f] [name_f]Cleo[/name_f] mentioned above):
[name_f][/name_f][name_f]Elle[/name_f] [name_f]Florence[/name_f]
[name_f][/name_f][name_f]Addison[/name_f] [name_f]Loretta[/name_f]
[name_f][/name_f][name_f]Maren[/name_f] [name_f]Reva[/name_f]
I tried to shoot for the stately-yet-modern feel of big bro’s name.
[name_f][/name_f]Hopefully these help!