First of all I really like
Cadence but I can't stand C- names spelled with a K. Why not spell it Caedence with the nn Caede? Or Caidence (but I don't like this spelling).
If you absolutely want to spell it with a K I think Kaidence is the best. I don't know if the NN
Kaede is so special to you that you don't want to change the spelling, but since it's also a name from the otori series (no idea what that is...) and it has a different pronounciation I think you could change the K to a C without spoiling the name.