I think
Lavender is a nice change from
Violet, which is quite popular now. It makes me think of the film
Matilda, with the little girl who was called
Lavender.
I don't think it really needs a nn. Lav? Ender? Purple?
using your style of names:
Lavender MarieLavender CaitlinLavender HaileyLavender RoseLavender DanielleLavender LaurenLavender CharlotteLavender Rachel
April LavenderAmy LavenderOlivia LavenderSarah Lavender
Any you like?