I don't think they are too similar at all. The initial sound is the only major similarity but I feel like some of that is negated by they fact that they start with different letters. I would use them together without question. I hope that makes sense.
I like them together!
I think they would be great sister names.
I think they would be fine.
I thought about those names for twins. We have the same name style. Love your names.
I think they sound great together!
Thanks for the feedback everyone! I am loving Juliette for our sibset!