Dawn was my SIL's middle name until she married my brother and dropped it for her maiden name. It's now my eldest niece's middle name.
Dawn is okay. I like its imagery, but not the sound (which is identical to
Don in my accent). I guess I'd call
Dawn the proto-Willow, but it doesn't really feel like a great fit with either of your word name categories.
I think
Dawn's best fit is with the word names of its heyday--more
Heather than
Willow, more
April than
Autumn, more
Crystal than
Destiny.