Hello!
I am also expecting twins (so good luck when it comes time to find out!), just no idea on which gender yet- however I absolutely [name_u]LOVE[/name_u] your name taste!
IMHO [name_f]Rosamund[/name_f] is slightly old fashioned, whereas [name_f]Rosalie[/name_f] is a modern and BEAUTIFUL revival of the name.
Personally I am not a fan of matching flower FNs for twins/sisters- however I am a big fan of flower names as middle names! (And actually as a FN for just one twin/sister)
Here are my top rated names out of your picks (in order):
[name_f]Astrid[/name_f] (in my top 5 names easily! Would be a contender for me if hubby liked it!)
[name_f]Cecily[/name_f] (classic, beautiful)
[name_f]Catherine[/name_f] (a fan, but mainly with the nickname ‘[name_f]Cate[/name_f]’)
[name_f]Daisy[/name_f] (a new favourite!)
[name_f]Iris[/name_f] (classic, beautiful, potentially too old fashioned)
[name_f]Bridget[/name_f] (I like, but prefer [name_f]Brigitte[/name_f])
My choice would be:
[name_m]Soren[/name_m] [name_m]Sebastian[/name_m] Freesman
[name_f]Leonora[/name_f] [name_f]Mary[/name_f] [name_f]Louise[/name_f] / [name_f]Phoebe[/name_f] [name_f]Elizabeth[/name_f] Galleher
[name_f]Rosalie[/name_f] [name_f]Violet[/name_f] [name_f]Maud[/name_f] / [name_f]Astrid[/name_f] [name_f]Daisy[/name_f] [name_f]Cecily[/name_f]
But in general, a formation of [name_f]Astrid[/name_f]/[name_f]Cecily[/name_f]/[name_f]Catherine[/name_f]/[name_f]Daisy[/name_f] would be my choice!
GOOD [name_m]LUCK[/name_m]!
All such lovely names! I love [name_f]Catherine[/name_f] [name_f]Daisy[/name_f] Keating with [name_f]Rosamund[/name_f] [name_f]Violet[/name_f] [name_f]Maud[/name_f]. Good luck! 
I think the person who said we can’t have a [name_f]Rose[/name_f] name with [name_f]Josephine[/name_f] is probably right - [name_f]Rosie[/name_f] and [name_u]Josie[/name_u]. Darn! But it takes one name off the list I guess…
Here is the list again (I’m just thinking out loud now!)
*[name_f]Astrid[/name_f] - I have loved this name for a long time and I think the combo suggested [name_f]Astrid[/name_f] [name_f]Daisy[/name_f] is super-cute but something stopped me last time and also now.
[name_f]Bridget[/name_f] - would go well with either [name_f]Rosamund[/name_f] r [name_f]Rosalie[/name_f] and our surname starts with a B
[name_f]Cecily[/name_f] - Classic with [name_f]Rosamund[/name_f], too rhyming with [name_f]Rosalie[/name_f]
*[name_f]Catherine[/name_f] - has to be in the top 2 or 3, elegant, love the [name_f]Catherine[/name_f] [name_f]Lily[/name_f] [name_u]Wren[/name_u] combo
[name_f]Daisy[/name_f] - am having huge crush on this name but it violates my no nn as names rule, so would I have to use [name_f]Margaret[/name_f]? And [name_f]Marguerite[/name_f] is just not for me.
[name_f]Iris[/name_f] - super romantic and old-fashioned, eldest son also likes this one (apparently is a pokemon name!)
*[name_f]Josephine[/name_f] - I think we have to rule this one out
*[name_f]Lily[/name_f] - Is so lovely but it is too popular. I’d never considered as a middle before but it goes really well.
[name_f]Shoshana[/name_f] - is a passing crush, I don’t think I could ever use it but the suggestion [name_f]Shoshana[/name_f] [name_f]Cecily[/name_f] [name_f]Snow[/name_f] was naming genius, I just wish I was that brave person who would call a daughter [name_f]Shoshana[/name_f] [name_f]Cecily[/name_f] [name_f]Snow[/name_f].
[name_f]Snow[/name_f] - def only a middle name contender.
[name_f]Tabitha[/name_f] - is perhaps in the end too cutesy.
[name_f]Thomasina[/name_f] - I am pleased and surprised by the positive feedback for this name, this is my gp
[name_u]Wren[/name_u] - this could really be a first name as well as a second - what a great name.
My fave combos so far are
[name_f]Catherine[/name_f] [name_f]Lily[/name_f] [name_u]Wren[/name_u]
[name_f]Iris[/name_f] [name_f]Shoshana[/name_f] [name_f]Snow[/name_f]
[name_f]Iris[/name_f] [name_f]Josephine[/name_f] [name_u]Wren[/name_u]
[name_f]Thomasina[/name_f] [name_f]Lily[/name_f] [name_f]Snow[/name_f] *[name_f]Daisy[/name_f] as a nn?
[name_f]Thomasina[/name_f] [name_f]Lily[/name_f] [name_u]Wren[/name_u]
[name_f]Henrietta[/name_f] [name_f]Josephine[/name_f] [name_f]Hope[/name_f] *[name_f]Hetty[/name_f]
[name_f]Henrietta[/name_f] [name_f]Frieda[/name_f] [name_f]Hope[/name_f] ([name_f]Frieda[/name_f] is for husband who has been wanting this name forever)
[name_f]Shoshana[/name_f] [name_f]Cecily[/name_f] [name_f]Snow[/name_f]
[name_f]Catherine[/name_f] [name_f]Lily[/name_f] Keating
[name_f]Catherine[/name_f] [name_u]Wren[/name_u] Keating
[name_f]Catherine[/name_f] [name_f]Daisy[/name_f] Keating
[name_f]Catherine[/name_f] [name_f]Thomasina[/name_f] Keating
I think you might like [name_f]Shona[/name_f], [name_f]Pippa[/name_f], or [name_f]Rita[/name_f]!
I prefer [name_f]Rosalie[/name_f] over [name_f]Rosemund[/name_f] (btw).
Favorites from your list:
[name_f]Rosalie[/name_f] & [name_f]Cecily[/name_f]
[name_f]Rosalie[/name_f] & [name_f]Tabitha[/name_f]
[name_f]Rosalie[/name_f] & [name_f]Snow[/name_f] (kind of prefer as a MN, but useable as a FN)