Well...Kyo and Kyoshiro...isn't his friendship with Kyoshiro his main motivator through a lot of the series? I don't think, though, that it's amorous in either case...I haven't seen all of his friendship with Kyoshiro, but with Kyo, it's more mutual respectand obsessive need to know who's better.

As far as Gojyo goes...Minekura said in the first volume that the person who's right for Gojyo might not be a woman...Gojyo I easily seeing going any which way that struck his fancy. But yeah, I think the presence of Hakkai and Sanzo helps distract people from Goku/Gojyo thoughts(thankfully) Plus, how could anyone possibly mistake them as anything but brother's squabbling(though I think a chunk of it is Goku picking up on Sanzo's problems with Gojyo and reacting to them, and Gojyo feeding off of that)