[name_f]Do[/name_f] you like [name_f]Rosa[/name_f] or [name_f]Rosamund[/name_f] better? DP and I are both open to both, but we each like different ones better. Also, what sibling do you think go with those names?
[name_f]Rosa[/name_f] - I like this one more, and DP is okay with it. It seems a little off that her first and middle name would both have 4 letters though ([name_f]Rosa[/name_f] [name_u]Jean[/name_u]). Is it too short or does it really not matter?
[name_f]Rosamund[/name_f] - Would probably be called [name_f]Rosa[/name_f] most of the time. I worry that she may be called [name_f]Rose[/name_f] by other people though, and I much prefer [name_f]Rosa[/name_f], in part because it’s less popular. Also, sounds to long and old-ladyish for a baby in my opinion. DP likes it more that [name_f]Rosa[/name_f] though.
I actually really like the sound of [name_f]Rosamund[/name_f] [name_u]Jean[/name_u] ” I’d say go for it and have [name_f]Rose[/name_f] as a nickname.
While I find [name_f]Rosa[/name_f] to be more zippy and upbeat I do like the romantic feel of [name_f]Rosamund[/name_f]. I like [name_u]Jean[/name_u] with both.
For siblings, with [name_f]Rosa[/name_f] I like other stylish and streamlined names such as [name_f]Greta[/name_f], [name_f]Ada[/name_f], [name_f]Edith[/name_f], [name_f]Frances[/name_f], [name_f]Matilda[/name_f], [name_f]Annabel[/name_f]. But all of these would work equally well with [name_f]Rosamund[/name_f] too. While many names would work well with either one as a sister, long or frillier names would be a more natural fit with [name_f]Rosamund[/name_f] - [name_f]Arabella[/name_f], [name_f]Evangeline[/name_f], [name_f]Georgette[/name_f], [name_f]Francesca[/name_f].
Tricky one!
I like Rosa for its sweet, simple elegance and Rosamund for its romance and drama. So despite their similar sounds, they are very different names to me in terms of style.
In your situation, I would probably go with Rosamund, because a) I think it flows better with super-short Jean in the middle, and b) it gives you the option to use both Rosa and Rosamund as you wish.
Siblings for Rosa:
Elle
Cleo
Ines
Pippa
Margot
Celia
Liv
Beatrix
Sylvie
Greta
Alice
June
Simon
Arthur
Oscar
Louis
Hugo
Benjamin
Thomas
Willem
Felix
Samuel
Henry
Jude
Siblings for Rosamund:
Guinevere
Georgiana
Clemency
Ferelith
Thomasin
Imogene
Heloise
Evangeline
Philippa
Winifred
Percival
Isidore
Dorian
Fabian
Lysander
Anatole
Ambrose
Willoughby
Hector
Evelyn
[name_f]Rosamund[/name_f] … [name_f]Rosamund[/name_f] {and} [name_f]Winifred[/name_f].
Hmm… I like [name_f]Rosa[/name_f] best but i think [name_f]Rosamund[/name_f] is possibly best for you - it goes well with [name_u]Jean[/name_u] and gives you [name_f]Rosa[/name_f].
Some siblings…
[name_f]Rosamund[/name_f] and…
[name_f]Cordelia[/name_f] - [name_f]Cora[/name_f]
[name_f]Dorothea[/name_f] -[name_f]Thea[/name_f]
[name_f]Cecilia[/name_f] - [name_f]Celia[/name_f], [name_f]Cece[/name_f], [name_f]Lia[/name_f]
[name_f]Felicity[/name_f] -Lissy, [name_f]Fia[/name_f], [name_f]Tia[/name_f]
[name_f]Matilda[/name_f] - [name_f]Tilda[/name_f], [name_f]Tilly[/name_f], [name_f]Mila[/name_f], [name_f]Millie[/name_f]
[name_u]Eloise[/name_u]/[name_f]Eloisa[/name_f] - [name_f]Ellie[/name_f], [name_u]Lou[/name_u], [name_f]Lula[/name_f]
[name_f]Emmeline[/name_f] - [name_f]Emmy[/name_f], [name_f]Lina[/name_f], [name_f]Millie[/name_f]
[name_f]Josephine[/name_f] -[name_u]Josie[/name_u], [name_f]Effie[/name_f]
[name_f]Caroline[/name_f] -[name_f]Cara[/name_f], [name_f]Callie[/name_f]
[name_f]Estelle[/name_f]/a - [name_f]Stella[/name_f]
[name_f]Verity[/name_f] - [name_f]Vera[/name_f]
[name_f]Rosa[/name_f] and…
[name_f]Lois[/name_f]
[name_f]Mabel[/name_f]
[name_f]Stella[/name_f]
[name_u]June[/name_u]
[name_f]Phoebe[/name_f]
[name_f]Vera[/name_f]
[name_f]Alice[/name_f]
[name_f]Mina[/name_f]
I would pick [name_f]Rosamund[/name_f]
Sibs are possibly:
[name_m]Alfred[/name_m], [name_f]Millicent[/name_f], [name_f]Georgina[/name_f], [name_m]Jasper[/name_m], [name_f]Cecily[/name_f], [name_f]Louise[/name_f], [name_m]Arthur[/name_m], [name_m]Wesley[/name_m]
I prefer [name_f]Rosa[/name_f], it’s more modern, but it’s still a very classic name. Neither are too popular either, at least here in the US. Have you considered spelling it [name_f]Jeanne[/name_f]? [name_f]Rosa[/name_f] [name_f]Jeanne[/name_f] has a nice look to it.
Sibling ideas:
[name_f]Rosa[/name_f] & [name_f]Vera[/name_f]
[name_f]Rosa[/name_f] & [name_f]Juliet[/name_f]
[name_f]Rosa[/name_f] & [name_f]Brigid[/name_f]
[name_f]Rosa[/name_f] & [name_f]Joanna[/name_f]
[name_f]Rosa[/name_f] & [name_f]Eve[/name_f]
[name_f]Rosamund[/name_f] & [name_f]Georgina[/name_f] (seconding this one)
[name_f]Rosamund[/name_f] & [name_f]Alessandra[/name_f]
[name_f]Rosamund[/name_f] & [name_f]Ingrid[/name_f]
[name_f]Rosamund[/name_f] & [name_f]Amelia[/name_f]
[name_f]Rosamund[/name_f] & [name_f]Yvonne[/name_f]
Thanks for all the help! I particularly love [name_f]Frances[/name_f], [name_f]Emmeline[/name_f], [name_f]Alessandra[/name_f], and [name_f]Estelle[/name_f]
[name_f]Louisa[/name_f] is also my favorite name of all time!
I prefer [name_f]Rosamund[/name_f], but I generally like longer and more elaborate names. If you would be calling her [name_f]Rosa[/name_f] most of the time anyways, I would just name her [name_f]Rosa[/name_f]. [name_f]Rosamund[/name_f] [name_u]Jean[/name_u] does sound better than [name_f]Rosa[/name_f] [name_u]Jean[/name_u] though. Not sure if that’s any help! 
I would choose [name_f]Rosamund[/name_f]! I think it sounds better with a short middle, and it also gives her lots of options in terms of what to go by. A true stand-out name! I would likely call [name_f]Rosamund[/name_f]'s sister something like [name_f]Cornelia[/name_f], [name_f]Beatrix[/name_f], [name_f]Cecily[/name_f], [name_f]Georgiana[/name_f], [name_f]Philippa[/name_f], [name_f]Dorothea[/name_f], [name_f]Lavinia[/name_f], [name_f]Theodosia[/name_f], [name_f]Susannah[/name_f], or [name_f]Morwenna[/name_f]: Names that have a lot of history and weight but are rare, or variations on classics.