[name_f]Lavinia[/name_f] [name_f]Garland[/name_f] / [name_f]Lavinia[/name_f] [name_f]Garnet[/name_f] / [name_f]Lavinia[/name_f] [name_f]Rosamund[/name_f] is what I’ve come up with thus far.
I prefer very feminine but not too frilly names with [name_f]Lavinia[/name_f], some of my favourites:
[name_f]Lavinia[/name_f] [name_f]Charlotte[/name_f]
[name_f]Lavinia[/name_f] [name_f]Pearl[/name_f]
[name_f]Lavinia[/name_f] [name_f]Maude[/name_f]
[name_f]Lavinia[/name_f] [name_f]Mabel[/name_f]
[name_f]Lavinia[/name_f] [name_f]Phoebe[/name_f]
[name_f]Lavinia[/name_f] [name_f]Rosemary[/name_f]
from the ones on your list, my favourite is [name_f]Lavinia[/name_f] [name_f]Rosamund[/name_f] as it fits my above criteria perfectly.
I actually really like [name_f]Lavinia[/name_f] [name_f]Daisy[/name_f]. I’ve considered this for a future daughter of my own! I tend to like long feminine first names with short, simple middles.
I struggle with [name_f]Lavinia[/name_f] due to the mean girl in A [name_m]Little[/name_m] [name_f]Princess[/name_f] which I watched twice a month for years when I was little, and still adore. It’s a wonderful sounding name, my mind just won’t even consider it. 
Wanted to say that [name_f]Garnet[/name_f] is lovely and does wonders for her ^^ [name_f]Lavinia[/name_f] [name_f]Garnet[/name_f] is gorgeous!
[name_f]Lavinia[/name_f] [name_f]Rosamund[/name_f] is really lovely!
[name_f]Lavinia[/name_f] [name_f]Bellatrix[/name_f]
[name_f]Lavinia[/name_f] [name_f]Persephone[/name_f]
[name_f]Lavinia[/name_f] [name_f]Beatrix[/name_f]
[name_f]Lavinia[/name_f] [name_f]Ivy[/name_f]
[name_f]Lavinia[/name_f] [name_f]Iris[/name_f]
[name_f]Lavinia[/name_f] [name_f]Daphne[/name_f]
[name_f]Lavinia[/name_f] [name_f]Imogen[/name_f]
[name_f]Lavinia[/name_f] [name_f]Helen[/name_f]
[name_f]Lavinia[/name_f] [name_f]Josephine[/name_f]
[name_f]Lavinia[/name_f] [name_f]Dahlia[/name_f]
[name_f]Lavinia[/name_f] [name_f]Opal[/name_f]
[name_f]Lavinia[/name_f] [name_f]Elisabet[/name_f]
[name_f]Lavinia[/name_f] [name_f]Jane[/name_f]
[name_f]Lavinia[/name_f] [name_f]Scarlet[/name_f]
[name_f]Lavinia[/name_f] [name_f]Willow[/name_f]
[name_f]Lavinia[/name_f] [name_f]Primrose[/name_f]
[name_f]Lavinia[/name_f] [name_f]Zoe[/name_f]
[name_f]Lavinia[/name_f] [name_u]Marian[/name_u]
I think a short or classic middle works best:
[name_f]Lavinia[/name_f] [name_f]Alice[/name_f]
[name_f]Lavinia[/name_f] [name_f]Catherine[/name_f]
[name_f]Lavinia[/name_f] [name_f]Carys[/name_f]
[name_f]Lavinia[/name_f] [name_f]Chloe[/name_f]
[name_f]Lavinia[/name_f] [name_f]Coral[/name_f]
[name_f]Lavinia[/name_f] [name_f]Emme[/name_f]
[name_f]Lavinia[/name_f] [name_f]Erin[/name_f]
[name_f]Lavinia[/name_f] [name_f]Eve[/name_f]
[name_f]Lavinia[/name_f] [name_f]Grace[/name_f]
[name_f]Lavinia[/name_f] [name_f]Margaret[/name_f]
[name_f]Lavinia[/name_f] [name_f]Margot[/name_f]
[name_f]Lavinia[/name_f] [name_f]Marie[/name_f]
[name_f]Lavinia[/name_f] [name_f]Maude[/name_f] (seconded!)
[name_f]Lavinia[/name_f] [name_f]Phoebe[/name_f]
[name_f]Lavinia[/name_f] [name_f]Rose[/name_f]
[name_f]Lavinia[/name_f] [name_u]Romy[/name_u]
[name_f]Lavinia[/name_f] [name_u]Rue[/name_u]
[name_f]Lavinia[/name_f] [name_f]Ruth[/name_f]
I like [name_f]Lavinia[/name_f] [name_f]Rosamund[/name_f]. S’more ideas…
[name_f]Lavinia[/name_f] [name_f]Elsbeth[/name_f]/[name_f]Elspeth[/name_f]
[name_f]Lavinia[/name_f] [name_f]Frances[/name_f]
[name_f]Lavinia[/name_f] [name_u]Morgan[/name_u]
[name_f]Lavinia[/name_f] [name_f]Marigold[/name_f]
[name_f]Lavinia[/name_f] [name_u]Poet[/name_u]
[name_f]Lavinia[/name_f] [name_f]Sparrow[/name_f]
[name_f]Lavinia[/name_f] [name_f]Hazel[/name_f]
[name_f]Lavinia[/name_f] [name_f]Kate[/name_f]/[name_f]Cate[/name_f]