I love
Cecilia. Not sure about all the S sounds, with
Scarlett &
Cecilia, but they at least don't start with the same letter so it's not cutesy-cutesy, imo. ;)
Of your combos, the only one I don't care for is
Cecilia Rose, just because
Rose is so 'blah' as a mn, I think. I think
Cecilia Primrose is my fave, though. But out of those 3, I don't think you can go wrong, really.