I'm not so much asking what they are, or have been, but what you think they should have been (using original version, retcons, retcons of retcons, general personality, whatever). Mostly during the sidekick era, but after they are grown is okay, too. But definitely looking at cross-generational relationships.

Started when I was reading this thread from last year and someone mentioned Hal having better relationships with some of the sidekicks than their mentors. That got me to thinking about Clark and Dick. I do think it gets played up too much by the fanndom (fanfic) sometimes, but yes, they were friends when he was a child, and we've seen them friends as adults. But in the early post-COIE-era, the relationship with Superman and Batman got a lot more distant. So Jason and Tim (who worked more independently anyway) never seemed to have the same degree of contact/closeness with him. Of course, Jason's shorter tenure as Robin and the change from multiple-stories-per-issue to multiple-issues-per-story over time contribute, too. But if you think Clark and Bruce should have been close all along, do you think Tim and Jason should be closer to Superman? Or if you like the distance and distrust, do you think Dick should have no particular relationship with him?

Dick's the only sidekick I can recall that interacted on-panel with any other adult characters much back when he was still a kid (well, Damian now, since he's buddies with Jon? or YJ with Red Tornado?). But are there any you think should have interacted off-panel? Or you would have do so in your headcanon?

Roy ended up with close relationships with Dinah and Hal, though of course, he was already an adult when they originally came on the scene. I like the relationships, though I wish Roy hadn't disappeared from Ollie's thoughts when the bronze age rolled around. And, even with Hal and Dinah, excepting the addiction issue (and stand-alone after-school special that other writers made work later), I don't really remember any relationship between Roy and the two being a thing until post-COIE.