I really like the name Juno. It seems like it would fit any type of person, and I just like the sound too - I like it better than June.
I don't know about it being too strongly associated with the movie. I haven't seen the movie Juno, but I'd say that it would have been lots of people's first encounter with the name and would then be what they first think of when hearing the name. But so many names have unpleasant associations, and I reckon most people won't think of the movie in a few years, or barely think of it now. I can speak for myself and say that I don't think of the movie at all when I hear the name - I think of Juno Temple!
I don't think having two -o endings is too much, I reckon it sounds quite nice. And any way, there are HEAPS of sisters whose names both end in -a or -ia or an 'ee' sound. I know two sisters called Mia and Sofia. I don't think names ending in the same letter/sound is any different from names starting with the same letter/sound.
Juno
Juno
Juno