They we dating.
We all knew it.
Jack done the blizzard of '68 to get Bunny to come see him.
Bunny when and got Jack to bring him to the other guardians because he wanted to see him.
They nearly kissed in front of the other guardians they wanted to but couldn't.
Bunny looked out of the sleigh to see if Jack was ok when he flew out because he cared.
They when after Pitch when he said no one belives in Jack because he would do anything for Jack.
Jack chagellend Bunny for collecting tooth because he wanted to get his attention.
They shared a sweet moment with Sophie.
Jack got Jamie to believe in Bunny.
Bunny saved Jack's life for Pitch.
So you have all the proof they were dating.