I grew up with a lot of Candaces. And
Candice,
Kandace, Kandyce, etc.
I think
Candace is actually a nice name. It's probably becoming retro-cool again soon.
Candy is.... a lot, though. Like I would have hated being called
Candy as a little kid. It's very infantalizing, and hard to pull off.
Candy is cute on a 2 year old, sure, but it doesn't age well.
I like
Candace as a middle name idea a lot.