Really? For me, the three current bots share an equal closeness to one another, The Spine sort of playing a big brother to the other two role despite Rabbit being first made.
For some reason, The Jon in my mind feels closer to HatchWorth than he does with Rabbit and The Spine. See, most of what I've seen with the The Jon, Rabbit, and The Spine interacting on stage involves The Spine and Rabbit talking, and generally expressing that The Jon was a bit weird. Rabbit went along with The Jon sometimes, but mostly it was The Spine and Rabbit talking whilst The Jon did what he wanted to do (especially later on). It's like, The Jon always belonged somewhere off in Kazooland, as though of all the bots he really wasn't meant to be here. I mean, The Spine is almost normal with his dry humor and resistance to being silly (probably his natural state IS silliness), and Rabbit doesn't really seem to care where he is, he's having a good time. The Jon? He was more like a dream... disconnected, as if he was seeing something completely different from what the other two bots were seeing.
I think that's something HatchWorth could understand... I don't know why.