After coming to the sad realisation that a little [name_m]Harrison[/name_m] would likely become [name_m]Harry[/name_m] (not a fan of [name_m]Harry[/name_m], I don’t like any [name_m]Harrison[/name_m] nicknames), I’ve gone to the next name on my list, [name_u]Leighton[/name_u] (pn [name_m]Lay[/name_m]-ton). I’m not entirely sure what sibling names would suit it, but my taste is classic for girls, and I love surnames and timeless names on boys (ie; [name_m]Henry[/name_m], [name_m]Lucas[/name_m], [name_m]William[/name_m], etc). I’ll take any suggestions you’ve got, but preferably no L names (not a fan of uber matchy sibling names). Thanks 
From your signature, I think [name_u]Leighton[/name_u] goes well with [name_u]Mackenzie[/name_u], [name_m]Bennett[/name_m], [name_m]Callum[/name_m], [name_u]Ashley[/name_u] and [name_u]Elliott[/name_u] ([name_m]Harrison[/name_m], [name_u]Addison[/name_u], [name_m]Lincoln[/name_m] and [name_m]Lochlan[/name_m] share an “n” ending with [name_u]Leighton[/name_u] so arent’ ideal for brothers). I can also see [name_u]Leighton[/name_u] with sisters named [name_f]Blythe[/name_f], [name_f]Florence[/name_f] and [name_f]Clementine[/name_f]. [name_u]Leighton[/name_u] is a surname with an English gentleman vibe so I would pair him with these names.
Boys
[name_u]Spencer[/name_u]
[name_u]Percy[/name_u]
[name_u]Parrish[/name_u]
[name_u]Stanley[/name_u]
[name_m]Maxwell[/name_m]
[name_u]Dean[/name_u]
[name_m]Clark[/name_m]
[name_m]Clive[/name_m]
[name_u]Sidney[/name_u]
[name_u]Ellis[/name_u]
[name_m]Miles[/name_m]
[name_m]Merrick[/name_m]
[name_m]Grant[/name_m]
[name_u]Emmett[/name_u]
[name_u]Douglas[/name_u]
[name_m]Garrett[/name_m]
[name_m]Harvey[/name_m]
[name_m]Wyatt[/name_m]
[name_u]Perry[/name_u]
[name_u]Everett[/name_u]
[name_u]Torrance[/name_u]
[name_m]Fraser[/name_m]
[name_u]Reilly[/name_u]
[name_u]Hollis[/name_u]
[name_u]Darcy[/name_u]
[name_m]Cabot[/name_m]
[name_u]Sawyer[/name_u]
[name_m]Stewart[/name_m]/[name_m]Stuart[/name_m]
[name_u]Mercer[/name_u]
[name_u]Dexter[/name_u]
[name_u]Schuyler[/name_u]
[name_u]Porter[/name_u]
[name_m]Faulkner[/name_m]
[name_u]Auden[/name_u]
[name_u]Campbell[/name_u]
[name_m]Griffith[/name_m]
[name_m]Hawthorne[/name_m]
[name_m]Montgomery[/name_m]
[name_m]Worth[/name_m]
[name_m]Bramwell[/name_m]
[name_u]Marlowe[/name_u]
[name_u]Sterling[/name_u]
[name_m]Wilder[/name_m]
[name_m]Clement[/name_m]
[name_u]Pascoe[/name_u]
[name_u]Willoughby[/name_u]
[name_m]Randolph[/name_m]
[name_m]Dashiell[/name_m]
Forsyth
[name_m]Armistead[/name_m]
[name_u]Calder[/name_u]
[name_m]Clarence[/name_m]
[name_m]Clifford[/name_m]
My first thought was [name_u]Leighton[/name_u] and [name_u]Mackenzie[/name_u], and then I saw [name_u]Mackenzie[/name_u] in your signature I would love that sibset. [name_u]Leighton[/name_u] and [name_m]Callum[/name_m] is also a sweet sibset for brothers. [name_f]Isabeau[/name_f] would be a cute sister name for [name_u]Leighton[/name_u], as would [name_f]Blythe[/name_f].