*snaps and makes a rant about how mint desperately needs a personality*
All of the JBR are fleshed out at least a little bit, even Sparkling has a defining personality. But Mint...how do I even put this? He doesn't have a personality. And, no, before you ask, playing the violin is not a personality.
And it doesn't get much better with his love interest, Coca Cookie. Literally EVERYTHING she says is about cocoa, and she doesn't have any other traits, really.
Compare with Vampire Cookie, who has a similar thing going on as Mint in that other than the JBR, he is mostly connected to one other character, Alchemist Cookie. However, unlike Mint, Vamp is very well fleshed out. He's laid back, takes things very slow, and is seen to be desperately searching for a purpose in life.
Compare with his sister, Alchemist Cookie, who is the polar opposite. She, like her brother, is seen to be desperately searching for a purpose in life. However, she takes a very different approach to it. Research and formulas are her life, she's hotheaded and mostly relies on external objects and research rather than her own ideas.
These two have very contrasting, yet very similar, personalities. It makes for a good dynamic between the two, and makes it fun to watch their antics as they yell at each other. Mint has none of this with Cocoa Cookie, as neither of them have any defining traits other than one. And this is where I believe Mint and Cocoa's characters and dynamic fall flat, it isn't interesting to see them interact with each other (or anyone at all, really) because they don't have personalities.
TL;DR Mint and Cocoa deserve to be as fleshed out as Vamp and Alchemist, the two other cookies with a similar gimmick to them that works well
