I'm sorry - in my opinion, yes, it's bad. You can't have it both ways. I would rather see you name her either
Kaede or
Cadence, not try to combine the two. Combining them into one spelling - or respelling the word
Cadence at all - to me sort of dumbs the name down, from a lovely concept-name to a "pretty sound and look." And as such it seems more trivial and shallow.
I think you'd be perfectly okay to name her
Cadence and call her
Kaede, and spell it like that, and say she's named in honor of
Kay.