I don't really care for any of those names but they aren't terrible.
If I had to have a 3-girl 1-boy nature sibset it would be
Phoenix,
Calanthe,
Zinnia, and
Astraea (some of these aren't direct nature names but they mean something nature-y).
I have cousins who are two sets of twins. The older ones are 18 and are
Cody and
Cory, and the younger ones are 16 and are
Brooke and
Mark (called Little
Mark, he was named after their dad).