I far prefer
Iris.
Kira could be
KIEra, could be KEEra, could be KEEara ... too much like hard work.
Iris is one of the very best flower names, and runs no risk of galloping popularity, unlike eg
Lily and
Rose.
If it were me, I'd take
Iris Winter Mariel (rather than
Marielle), but
Winter Ellia is also fine. Or, what about
Iris Ellia
Wynne?