Ok, so this is either a stroke of genius or a really bad idea…
Rank the previous poster’s names from who you think would be the oldest sibling/child at the top, down to the youngest child at the bottom.
For example:
[name_m]Cedric[/name_m] (oldest)
[name_m]Philip[/name_m]
[name_m]Linus[/name_m]
[name_m]Wesley[/name_m] (youngest)
Have fun! First poster can do mine! 
Philip (oldest)
[name_m]Wesley[/name_m]
[name_m]Cedric[/name_m]
[name_m]Linus[/name_m] (youngest)
Rowan, [name_u]Vivian[/name_u], [name_f]Ophelia[/name_f], [name_u]Jameson[/name_u]
[name_u]Vivian[/name_u] (oldest)
[name_f]Ophelia[/name_f]
[name_u]Jameson[/name_u]
[name_u]Rowan[/name_u] (youngest)
[name_f]Gwen[/name_f], [name_f]Fern[/name_f], [name_f]Heidi[/name_f], [name_u]June[/name_u]
I think the order in which you put them feels very natural.
[name_f]Gwen[/name_f]
[name_f]Fern[/name_f]/Heidi
[name_f]Heidi[/name_f]/Fern
[name_u]June[/name_u]
Hugo, [name_m]Edgar[/name_m], [name_m]Henry[/name_m], [name_f]Rose[/name_f], [name_f]Flora[/name_f]
Jonas
[name_f]Esther[/name_f]
[name_f]Felicity[/name_f]
[name_f]Lola[/name_f] 
Aaliyah, [name_f]Deja[/name_f], [name_f]Kiara[/name_f], [name_f]Stormi[/name_f] & [name_f]Milani[/name_f]
Milani & [name_f]Aaliyah[/name_f] (I feel like they’d be twins, but if not then [name_f]Milani[/name_f] is the older one)
[name_f]Kiara[/name_f]
[name_f]Deja[/name_f]
[name_f]Stormi[/name_f] (and I feel like [name_f]Stormi[/name_f] would be quite a bit younger than [name_f]Deja[/name_f])
Ottilie, [name_f]Ada[/name_f] & [name_f]Flora[/name_f]
Ada
[name_f]Ottilie[/name_f]
[name_f]Flora[/name_f]
Theodore, [name_f]Phoebe[/name_f], [name_f]Eloise[/name_f], & [name_u]Oliver[/name_u]
@futuremama
[name_f]Pheobe[/name_f]
[name_m]Theodore[/name_m]
[name_u]Oliver[/name_u]
[name_f]Eloise[/name_f]
Clara, [name_m]Felix[/name_m], [name_m]Isaac[/name_m], [name_f]Rose[/name_f]
Isaac
[name_f]Clara[/name_f]
[name_m]Felix[/name_m]
[name_f]Rose[/name_f]
Josepha, [name_f]Amalie[/name_f], [name_m]Ludwig[/name_m], [name_m]Julius[/name_m]
[name_m]Ludwig[/name_m]
[name_f]Josepha[/name_f]
[name_f]Amalie[/name_f]
[name_m]Julius[/name_m]
[name_f]Elizabeth[/name_f] “[name_f]Betsey[/name_f],” [name_f]Madeleine[/name_f] “[name_f]Nell/name_f,” and [name_m]Theodore[/name_m] “[name_u]Rory[/name_u].”
[name_m]Hugo[/name_m]
[name_f]Louisa[/name_f] (this and [name_m]Hugo[/name_m] are interchangeable)
[name_u]Claude[/name_u]
[name_f]Fern[/name_f] (she’s the baby )
[name_f]Anya[/name_f], [name_f]Rose[/name_f], [name_u]Marie[/name_u], [name_m]Linus[/name_m]
[name_f]Anya[/name_f]
[name_u]Marie[/name_u]
[name_f]Rose[/name_f]
[name_m]Linus[/name_m]
[name_f]Margaret[/name_f], [name_m]William[/name_m], [name_f]Katherine[/name_f], [name_u]George[/name_u]
Margaret (oldest)
[name_f]Katherine[/name_f]
[name_m]William[/name_m]
[name_u]George[/name_u]
Cassian, [name_m]Lysander[/name_m], [name_f]Elowen[/name_f], and [name_f]Persephone[/name_f]
Lysander (oldest)
[name_f]Persephone[/name_f]
[name_m]Cassian[/name_m]
[name_f]Elowen[/name_f] (youngest)
Isaiah, [name_u]Jasper[/name_u], [name_m]Felix[/name_m], and [name_f]Eleanor[/name_f]?
Jasper, [name_f]Eleanor[/name_f], [name_m]Isaiah[/name_m], then little [name_m]Felix[/name_m]
Ronan, [name_u]Dorian[/name_u], Fenrin, [name_m]Laszlo[/name_m], and [name_f]Cecily[/name_f]
Cecily (oldest)
[name_m]Ronan[/name_m]
[name_m]Laszlo[/name_m]
[name_u]Dorian[/name_u]
Fenrin (youngest)
Simon, [name_f]Ida[/name_f], [name_u]Levi[/name_u], and [name_f]Mary[/name_f]
[name_f]Mary[/name_f] (oldest)
[name_f]Ida[/name_f]
[name_m]Simon[/name_m]
[name_u]Levi[/name_u]
[name_u]Skye[/name_u], [name_f]Rosalind[/name_f], [name_f]Jane[/name_f], [name_f]Elizabeth[/name_f], [name_u]Benjamin[/name_u], [name_f]Lydia[/name_f]
Jane (oldest)
[name_f]Lydia[/name_f]
[name_f]Rosalind[/name_f]
[name_f]Elizabeth[/name_f]
[name_u]Benjamin[/name_u]
[name_u]Skye[/name_u]
Nadia, [name_f]Maeve[/name_f], [name_u]Harlow[/name_u], [name_f]Valeria[/name_f], [name_f]Aria[/name_f].
Lev (oldest)
[name_u]Jesse[/name_u]
[name_f]Adrienne[/name_f]
Ambrose, [name_u]Florian[/name_u], [name_u]Basil[/name_u], [name_f]Isadora[/name_f], [name_f]Rosalind[/name_f]
Isadora (oldest)
[name_m]Ambrose[/name_m]
[name_u]Florian[/name_u]
[name_f]Rosalind[/name_f]
[name_u]Basil[/name_u]
Alice, [name_f]Charlotte[/name_f], [name_m]Mathias[/name_m], [name_m]Bastien[/name_m]