I think if you go with Darcie for a girl you need a feminine middle name..

Darcie Juliette
Darcie Makenna
Darcie Chanel
Darcie Sheree

I like Charlie Flynn for a boy
Other middle names..

Charlie James
Charlie Ryan
Hm can't think of any other but I think it sounds best with a 1 syllable middle name..

Good luck in choosing a name for your little one