What do you think of this combo? Is it too much, or a terrible match? Does a 3/3 syllable match work?
My first instinct was that it did not work, but the more I said it the more lovely I though it sounded. (Personally, I have alliterative first and middle names, so in a way it was almost familiar having the repetitive sounds.)
I think it’s sweet! It’s a little long but has plenty of NN options if she wants something shorter. I love both names individually so together they are fin to me 
My name is [name]Cynthia[/name] [name]Celina[/name] (3-3, both names start with Cs and end with an “ah” sound) and I love it. I think [name]Gwendolen[/name] [name]Genevieve[/name] is lovely. Your daughter might not like learning to write her name, lol, but beyond that it is great!