[name_f]Suzannah[/name_f] is my favorite
[name_f]Rosalyn[/name_f] is also an option.
Maybe:
Samantha
Cassandra
Savannah
Selena
Seraphina
Serenity
Shekinah
Sydney
Sidony
Sienna
Sonia
I’d also go with [name_f]Susannah[/name_f]/[name_f]Susan[/name_f] for nickname [name_u]Sunny[/name_u], but I like pp’s suggestion of [name_f]Sunniva[/name_f]
I like [name_f]Susannah[/name_f]. [name_f]My[/name_f] friends niece is called [name_u]Emerson[/name_u] and she gets the nickname sunny a lot so you could use a name ending in a -son even though they seem pretty boyish to me, but the nickname sunny makes me like them more
I think [name_u]Sunny[/name_u] works for any name; it’s an adjective that could fit and smiling or happy baby.
[name_f]Susannah[/name_f] ([name_f]Susanna[/name_f], [name_f]Susan[/name_f], [name_f]Suzanne[/name_f]), [name_f]Alison[/name_f], and [name_f]Sunniva[/name_f] are the obvious choices, but what about:
[name_f]Alexandra[/name_f]
[name_f]Cassandra[/name_f]
Lysandra
[name_f]Roxanne[/name_f]
[name_f]Constance[/name_f]
[name_f]Alexandra[/name_f] Feodorovna was called [name_u]Sunny[/name_u] by her husband, Tsar [name_m]Nicholas[/name_m] II of [name_f]Russia[/name_f]. I actually really like [name_f]Alexandra[/name_f] nicknamed [name_u]Sunny[/name_u].
[name_m]How[/name_m] about names whose meanings are associated with the sun or qualities of the sun:
[name_f]Marisol[/name_f], [name_f]Soleil[/name_f], [name_f]Solana[/name_f] - sun
[name_f]Aurora[/name_f], [name_f]Zora[/name_f] - dawn
[name_f]Cressida[/name_f] - gold
[name_f]Phoebe[/name_f], [name_f]Ilona[/name_f], [name_f]Niamh[/name_f], [name_f]Helen[/name_f], [name_f]Eleanor[/name_f], [name_f]Elena[/name_f] - bright, shining, radiant etc
[name_f]Stella[/name_f], [name_f]Aster[/name_f] - star
[name_f]Clio[/name_f] - glory
Etc.
[name_m]Even[/name_m] names meaning happy or blonde could work. ([name_f]Felicity[/name_f], [name_f]Beatrice[/name_f]… [name_f]Xanthe[/name_f], etc.)
I still love [name_f]Sunday[/name_f], and also have [name_f]Phoebe[/name_f] on my short list, and had never thought of using [name_u]Sunny[/name_u] as a nickname due to meaning. That’s brilliant!
I also love [name_f]Susannah[/name_f], such a sweet name.