Kennet because it just sounds odd to me.
Alan because it sounds sort of sleazy...
Boys
CHRISTIANDAVIDFINLAYHAYDNHENRYKIEFERMATTEOMATTHIASQUINNSIDNEY
Rhiannon because it just doesn't sound right.
Hope because it is too "precious" for my taste.
Girls':
ARIAELLAGRACEHELENAJULIAMIRANDAOLIVIAOPHELIAROSEMARYWILLOW