Having said I’d go [name_f]Sylvie[/name_f] (because I prefer it to [name_f]Sylvia[/name_f] and think it’s easier spelling), I think you have good reasons to use [name_f]Sylvi[/name_f]. [name_m]Kasper[/name_m] & [name_f]Kaia[/name_f] is a little too matchy for me but could work too.
[name_f][/name_f]How about:
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Tindra[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Maren[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Celeste[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Meadow[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Pearl[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Winter[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Aurora[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Aneira[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Bryony[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Juniper[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Astrid[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Saffron[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Delphine[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Maple[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Soleil[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Willow[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Paloma[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Bloom[/name_f]
[name_f][/name_f][name_f]Sylvi[/name_f] [name_f]Searose[/name_f]