I like
Zoe Rebecca and
Deena Rachel.
I love the name
Deena or
Dina - it first caught my attention as the name of the gorgeous actress
Dina Meyer.
All the sources I've found agree that
Dina is probably a form of
Dinah, Hebrew meaning 'judged' in an apparently positive sense (vindicated by God?). One of them suggests that it is a short form of names ending in -dina such as Claudina, Bernardina, maybe even
Adina (another biblical name). I think it's safe to choose for yourself among these possible meanings, because there's no way any one of them could be affirmatively documented, and different instances probably have different origins.
I like your first three boy combos together too. Personally, if I were using biblical boy names I'd pick
Ira as the third name because I like the sound of it :-), but
Jared probably "fits" better with the general feel of
Nathan and
Simon.