We’re expecting a baby girl in [name_f]October[/name_f], and I love the nn [name_f]Sunny[/name_f]. I personally don’t really like nicknames as full names - no shade or judgement, it’s just never really been my vibe - so I’d like to find a full name option that gets us to that nn.
I may be looking for a unicorn, but I’d love to find a more classic/vintage name that goes with big sister [name_f]Eloise[/name_f]. Any thoughts?
Middle name will likely be [name_f]June[/name_f].
[name_f]Sonia[/name_f]
[name_f]Sunniva[/name_f]
[name_f]Sunday[/name_f]
[name_f]Sunisa[/name_f]
Names that end in son (Addison, [name_f]Allison[/name_f], [name_f]Madison[/name_f], etc.)
[name_f]Sonora[/name_f]
For classics [name_f]Susannah[/name_f] or [name_f]Allison[/name_f] nn [name_f]Sunny[/name_f] would work well
[name_f]Sunniva[/name_f]
[name_f]Summer[/name_f]
Ansonia/ [name_f]Annesonia[/name_f]
[name_f]Sonia[/name_f]
[name_f]Payson[/name_f]
[name_f]Sonora[/name_f]
[name_f]Sennen[/name_f]
[name_f]Susannah[/name_f] was my first thought - as suggested by @LibelluleClaire
Maybe…
[name_f]Cassandra[/name_f] → Sanny → [name_f]Sunny[/name_f]
[name_f]Sidonie[/name_f] / [name_f]Sidony[/name_f] → Sony → [name_f]Sunny[/name_f]
[name_f]Silvana[/name_f] / [name_f]Silvania[/name_f] → Sanny → [name_f]Sunny[/name_f]
[name_f]Simone[/name_f] → [name_m]Sonny[/name_m] → [name_f]Sunny[/name_f]
[name_f]Sophronia[/name_f] → [name_m]Sonny[/name_m] → [name_f]Sunny[/name_f]
[name_f]Solange[/name_f]
Solène
[name_f]Soline[/name_f]
[name_f]Soleil[/name_f]
[name_f]Persephone[/name_f]
[name_f]Saffron[/name_f]
Ohh these are all so unique!! I’m sort of obsessing over [name_f]Susannah[/name_f] now…that’s gorgeous!
Yeah, [name_f]Susannah[/name_f] [name_f]June[/name_f] is stunning
Sunny is a great everyday name. And having a full name option is also a good idea.
Here’s another post on this topic:
Another similar thread: Full name for nickname Sunny
[name_f]Summer[/name_f] could work, since the sun is out in [name_f]Summer[/name_f].
Also names meaning light or (as Nameberry suggests) “brilliant:”
[name_f]Lucy[/name_f]
[name_f]Claire[/name_f]
[name_f]Chiara[/name_f]
Names meaning shine or glow:
[name_f]Glory[/name_f] / [name_f]Gloria[/name_f]
[name_f]Aurora[/name_f]
[name_f]Iris[/name_f] (as in arcoíris 
)
[name_f]Sunshine[/name_f] and [name_f]Susannah[/name_f] are my faves!!
I think if the first name starts with and “S” and the middle name is [name_f]June[/name_f]. Combining those names could be [name_f]Sunny[/name_f]. [name_f]My[/name_f] mom’s friend’s name is [name_m]Robin[/name_m], but she called her sunshine because of her personality (very opposite sunshine hahaha). So you could choose another name and just call her sunny / [name_m]Sonny[/name_m] 
[name_f]Allison[/name_f], [name_f]Maddison[/name_f], [name_f]Sonia[/name_f] — anything with -son
[name_f]Savannah[/name_f] [name_f]June[/name_f]
[name_f]Solena[/name_f] [name_f]June[/name_f]
[name_f]Sonora[/name_f] [name_f]June[/name_f]
[name_f]Cassondra[/name_f] / [name_f]Sondra[/name_f]
[name_f]Sunday[/name_f] / [name_f]Sundae[/name_f]
[name_m]Hudson[/name_m], [name_m]Greyson[/name_m], Johansson — more gender neutral / masculine
[name_f]Hope[/name_f] this helps! Good luck
Another vote for [name_f]Susannah[/name_f]! [name_f]Gorgeous[/name_f] underused name that goes perfectly with [name_f]Eloise[/name_f].
[name_f]Susannah[/name_f] sounds like it could be a winner for you. It fits perfectly as a sister to [name_f]Eloise[/name_f] and is an intuitive way to get to nn [name_f]Sunny[/name_f].
[name_f]Summer[/name_f], [name_f]Susannah[/name_f] or [name_f]Susanna[/name_f], [name_f]Solena[/name_f] and [name_f]Sunday[/name_f] were all suggested which I love for you! Another one is [name_f]Solana[/name_f] (“sol” meaning sun)
I personally think it’s a bit of a stretch, but some people consider [name_m]Sonny[/name_m] a potential nickname for any name that ends in -son, so with that logic, a name like [name_f]Madison[/name_f], [name_f]Addison[/name_f] or [name_m]Emerson[/name_m] could get you to [name_f]Sunny[/name_f] 
I considered just [name_f]Sunny[/name_f] for a girl when I was pregnant and using a longer traditional middle name like [name_f]Elizabeth[/name_f] to “even it out” (I ended up having a boy, who goes by [name_m]Sonny[/name_m] 
) although you said you’re not into nickname names it could be an idea.
congrats and good luck!!
Immediate thoughts were:
-Addison June.
-Allison June.
-Ellison June.
-Emerson June.
-Jamison June.
-Madison/Maddison June.
-Sabrina June.
-Sophia/Sophie June.
-Solara June (meaning “of the sun”).
-Soleil June (means “sun” in French and pairs well with Eloise).
-Solene June (same description as with Soleil).
-Solange June (same description as with Soleil).
-Solstice June.
-Suzette June.
-Sunday June.
-Sunniva June.
-Sunehra June (meaning “golden” in Urdu).
-Savannah June.
-Susannah June.
-Samantha June.
I know not all these are classic/vintage, but I tried my best. 
I think [name_f]Eloise[/name_f] and Susana/Susannah (Sunny) could be a lovely sister set.