I like [name_m]Augustine[/name_m] for you – distinctive but familiar – while the nicknames make it more in the style of your son’s first name
[name_m]Francis[/name_m] is nice too – classic but a little unexpected like your daughter’s name.
[name_m]Everett[/name_m] is also a great choice – gentle but cool. It did make me think though of skipping straight to [name_m]Rhett[/name_m]? Something like [name_m]Rhett[/name_m] [name_m]Augustine[/name_m]?
If I were to suggest some first and middle name ideas…
[name_m]Jasper[/name_m]
[name_m]Felix[/name_m]
[name_m]Lyle[/name_m]
[name_m]Magnus[/name_m]
[name_m]Oscar[/name_m]
[name_m]Swithun[/name_m]
[name_m]Sylvester[/name_m]
[name_m]Beckett[/name_m]
[name_m]Vincent[/name_m]
[name_m]Julian[/name_m]
[name_m]Conrad[/name_m]
[name_m]Elias[/name_m]
[name_m]Ignatius[/name_m]
[name_m]Luca[/name_m]
[name_m]Crispin[/name_m]
[name_m]Louis[/name_m]
[name_m]Otto[/name_m]
[name_m]Nicodemus[/name_m]
[name_m]Nico[/name_m]
[name_m]Ralph[/name_m]
[name_m]Raymond[/name_m]
[name_m]Dean[/name_m]
For girls, I like the simplicity of [name_f]Jane[/name_f] – strong, sweet and versatile. [name_f]Alice[/name_f] is nice too – light and energetic but sturdy too. [name_f]Clara[/name_f] is sunny and lovely, so long as you don’t mind using [name_f]Clara[/name_f] with [name_f]Claire[/name_f] (same name, just variants)
Suggestions…
[name_f]Celia[/name_f]
[name_f]Sylvia[/name_f]
[name_f]Anna[/name_f]
[name_f]Florence[/name_f]
[name_f]Petra[/name_f]
[name_f]Sabrina[/name_f]
[name_f]Ellen[/name_f]
[name_f]Hazel[/name_f]
[name_f]Nina[/name_f]
[name_f]Honor[/name_f] / [name_f]Honoria[/name_f]
[name_f]Edith[/name_f]