Symphany reminds me of 'sympathy' as well. I'd much rather it be spelled Symphony. I do like it's sound but not really into it as a name.
Sonnet is cute. It makes me think of sunshine, bonnets, wildflowers, and books. I could get behind that purely for the image I get.
Sistine isn't terrible but it makes me think of 'cystic'.
I don't like them all together. I think they're way too matchy.
http://www.babynames.com/namelist/9852886