I think Camren seems like the odd one out. It also looks too close to
Carmen (I initially read it as
Carmen). Do you like
Carmen? I think it would fit better with the sibset and it would sound as rhymey with
Maren.
I love
Declan and I like
Maren a lot.
Camden is fine too, just not my style.
Declan John is a nice combo.
Both of your
Camden combos are good. I prefer
Camden Richard slightly.
Maren Cecilia is beautiful.
I think both
Cameron and
Camryn are better spellings than Camren (for the above reason and it also looks awkward).
Cameron Emma or
Cameron Roxanna would be my picks for flow.