I think [name_f]Charlotte[/name_f] goes great with [name_f]Madeline[/name_f], [name_u]William[/name_u], and [name_f]Maeve[/name_f], and makes sure [name_u]William[/name_u] won’t feel left out being the only one without an M name!
I love [name_f]Charlotte[/name_f] with the others - [name_f]Molly[/name_f] originates as a nickname while the rest are full names, so I think [name_f]Charlotte[/name_f] goes really well with them. I also like the fact that [name_f]Charlotte[/name_f] and [name_u]William[/name_u] don’t have an M initial, making the four names balance nicely
I would pick [name_f]Charlotte[/name_f] - because it’s a beautiful and strong name like your others, and it’s a full name too - you can use [name_f]Lottie[/name_f] as a nickname which is gorgeous and has the same sweetness as [name_f]Molly[/name_f].
Youngest children often get a more youthful / cutesy sounding name - and [name_f]Molly[/name_f], I think, will make her feel even more like the baby of the house (which she’ll love and feel mostly great about but that’s another story!).
If you want to keep M names for all the girls - and this could be a sweet pattern and fun! - I would go [name_f]Mary[/name_f], [name_f]Marianne[/name_f], [name_f]Margaret[/name_f] or [name_f]Marigold[/name_f] nn [name_f]Molly[/name_f]. I find [name_f]Mary[/name_f] so charming especially with [name_u]William[/name_u].
I like the name [name_f]Grace[/name_f] but as a name obsessive I’m not entirely relaxed (the sentence could end there ) about it coming right after [name_f]Maeve[/name_f]. [name_f]Maeve[/name_f] ‘n [name_f]Grace[/name_f] sounds harsh to me. You also might get [name_u]Will[/name_u] & [name_f]Grace[/name_f] but that doesn’t bother me so much as it’s now a very old show and they’re not twins.
I still prefer [name_f]Charlotte[/name_f] or a full name version of [name_f]Molly[/name_f] (as above - but also maybe Margot?). But I do really like [name_f]Grace[/name_f] and individual names always more important than “sibset”.
I would go ….M@deleine, Willi@m, M@eve and [name_f]Margot[/name_f].
There is something in me that doesn’t want to break the M pattern with the girls’ names and though I love the name, [name_f]Molly[/name_f], it seems to not go as well with the more formal names of the other siblings. [name_f]Margot[/name_f] seems like a better fit, but you could use [name_f]Molly[/name_f] as a nickname.