I love both [name]Emmeline[/name] and [name]Annabel[/name], but something about pairing them seems too perfect or too familiar (as libbyj also noted). [name]Henrietta[/name] fits with [name]Emmeline[/name], but has its own distinctive vibe. I think that using a nn for one child, but not another is perfectly fine. [name]Hetty[/name] is ok, but I love [name]Etta[/name].