And funny you should mention the Gojyo/Kougaiji comparison -- in Minekura's own color art she usually draws Gojyo with the same general complexion as the rest of the ikkou while Kou and Lirin are distinctly more tan...but I've seen artbook pieces where for whatever reason of artistic license, Kou and Lirin are lighter than usual. Meanwhile in the anime, for some reason they gave Gojyo (and Kenren, in the Gaiden flashback episodes) the same sort of tan complexion...perhaps to play up the Gojyo/Kou/Doku connection, and then by extension to make the Gojyo/Kenren parallel clearer? (The anime also redid Kenren's hair from black to red...and just to add to the confusion, Minekura has since done the occasional redheaded Kenren artbook pics.)

So even though the covers and artbooks really don't support it, the earlier immersion in the anime means that in my head, Gojyo tends to be a little more tanned than the rest of the guys. I mostly handwave it away by telling myself that he's far more likely to strip down and wander about scantily-clad or shirtless than the rest, so of course he's gotten a bit more sun and it should show...never mind that they're all spending hours in an open jeep every day so you'd think everybody would be at least tanned on their faces and hands, if not chronically sunburnt...I'm sure it's just that mother-hen Hakkai nags everybody not to forget the sunblock in the morning. *chuckle*

(And at least you're able to tan! I'm one of those folks who pretty much burns under a strong light bulb, which seems a particularly cruel genetic joke. I've tried, believe me, it just doesn't happen; my skin has only three states, the baseline pale, the slightly sallower pale that comes with small amounts of sun, and cooked lobster.)