How exciting! Fingers crossed 
Your names as a whole sound historical, romantic/ storybook epic, and distinct.
[name_f]Leonie[/name_f] is so sweet! I personally would go [name_f]Leonor[/name_f] nn [name_f]Leonie[/name_f] but straight to [name_f]Leonie[/name_f] makes more sense! It’s both bubbly annd cheerful, and smart and reliable.
I really [name_f]Apolline[/name_f], but someone almost
ruined it by saying they hear “appalling”. So I would go for [name_f]Pomeline[/name_f] or [name_f]Ottoline[/name_f] or another dreamy -ine name.
[name_f]Léontine[/name_f] - nn [name_f]Leonie[/name_f] could be good - as a cross between [name_f]Leonie[/name_f] and [name_f]Apolline[/name_f] and gives nn [name_f]Leonie[/name_f].
[name_m]Not[/name_m] sure about [name_f]Isola[/name_f] - I need to get used to it (not sure the sound is as charming to me).
I prefer [name_f]Sylvie[/name_f] to [name_f]Sylvana[/name_f] but that could be a nickname and [name_f]Sylvana[/name_f] might be more significant for your heritage (eg Slavic, Italian etc).
I love [name_m]Ambrose[/name_m] & really like [name_m]Cassian[/name_m] too. [name_m]Cass[/name_m] is a cute nn for a guy.
[name_m]Other[/name_m] names you might like:
[name_f]Ottilie[/name_f]
[name_f]Odette[/name_f]
[name_f]Olympia[/name_f]
[name_f]Romilly[/name_f]
[name_f]Ariadne[/name_f]
[name_f]Florence[/name_f]
[name_f]Zélie[/name_f]
[name_f]Matilde[/name_f]
[name_f]Elodie[/name_f]
[name_f]Allegra[/name_f]
[name_f]Aveline[/name_f]
[name_f]Celestine[/name_f]
[name_f]Sabine[/name_f] / [name_f]Sabina[/name_f]
[name_f]Bernadette[/name_f]
[name_f]Evangeline[/name_f]
[name_f]Seraphine[/name_f]
[name_f]Jessamine[/name_f]
[name_m]Benedict[/name_m]
[name_m]Vincent[/name_m]
[name_m]Florian[/name_m]
[name_m]Hugo[/name_m]
[name_m]Felix[/name_m]
[name_m]Octavian[/name_m]
[name_m]Tobias[/name_m]
[name_m]Augustin[/name_m]
[name_m]Rupert[/name_m]
[name_m]Emrys[/name_m] (too M heavy?)
[name_m]Casper[/name_m]
[name_m]Caspian[/name_m]
[name_m]Winston[/name_m]
[name_m]Orlando[/name_m]
[name_m]Tolliver[/name_m]
[name_m]Perrin[/name_m]