What do you think of [name_m]Fabian[/name_m] (is it FAHbien or [name_m]FAYbien[/name_m], anyway?), Cornelius, [name_u]Ashley[/name_u] (b), and [name_u]Charley[/name_u] as a sibset? NOTE: THIS IS HYOPTHETICAL. [name_m]DON[/name_m]'T WORRY THAT I’LL ACTUALLY USE THESE NAMES. 
I pronounce [name_m]Fabian[/name_m] [name_f]Fay[/name_f]-bien. I think the sibset isn’t very cohesive, [name_f]IMO[/name_f].
I know a [name_m]Fabien[/name_m] ([name_f]FAY[/name_f]-bee-in).
I would split this sibset into 2.
1: [name_m]Fabien[/name_m] and [name_m]Cornelius[/name_m]
2. [name_u]Ashley[/name_u] and [name_u]Charley[/name_u]
Why [name_u]Ashley[/name_u] for a boy? It’s a girls name!
[name_u]Ashley[/name_u] and [name_u]Charley[/name_u] stick out like sore thumbs. They are more dated/trendy while [name_m]Fabian[/name_m] and [name_m]Cornelius[/name_m] are uncommon and posh. I could see [name_m]Fabian[/name_m] and [name_m]Cornelius[/name_m] working in a sibling set. [name_m]Both[/name_m] [name_m]Fabian[/name_m] pronunciations are correct. I use the FAH one. [name_m]Fabian[/name_m] has three different pronunciations according to BehindtheName.
FAH-bee-ahn ([name_m]German[/name_m], Dutch), FAH-byahn (Polish), [name_f]FAY[/name_f]-bee-ən (English)
Is [name_u]Charley[/name_u] for a boy or girl? If it’s a girl, what about [name_f]Charlotta[/name_f], [name_f]Charlotte[/name_f] and [name_f]Charlize[/name_f] nicknamed [name_u]Charley[/name_u] or [name_m]Charles[/name_m] for a boy?
I think [name_m]Asher[/name_m] would be nice with [name_m]Fabian[/name_m].
@waverly123
[name_u]Ashley[/name_u] isn’t a girls name. It was originally a boys names, but became popular for girls in I believe the 80’s. It’s considered unisex now, but like the OP I prefer it for a boy.