I think
Iris is lovely, and
Iris Arabella is a great combo. I agree its better than
Lily and
Rose which are overused, which I suppose also applies to
Poppy in the UK.
I don't think having the same initials is weird.
P.S. Try not to use the term "OCD" to refer to "very particular." One is a mental illness that ruins lives and the other is a personality trait.