I wasn't able to get many BL novels when I was in middle and high school, only those I could slip under the radar of my homophobic-adjacent parents. FAKE and Gravitation were the only ones, and I don't like Gravitation... I do love FAKE though, because it included murder / mystery and it was a slow-moving monogamous relationship. I figured I could get that one without them noticing what it was because it has guys with guns on the cover, that surely can't be "gay" can it, even with all the flowers, lol. I usually re-visit it once a year, maybe the fact it was the "first" is part of my attachment to it.
I definitely do see Riku's feelings towards Sora as canon. I feel the same way about Isa and his out-of-control jealousy over Lea, but now, as Zackarix mentioned, there's the female character being introduced to divert away from that and "re-write" the story in a sense. Wasn't Xehaqus practically confirmed a while back (the company promoted the two on some LGBT day) or am I just remembering wrong? I thought it was a shame they'd probably only allow that because they were both more irredeemable villains. Why not do that with Saix and Axel at least? /sigh
For me, I can't really get into Xehaqus because I never really liked either character. I think what that ship is ideally going for reminds me of Magneto / Xavier or Dumbledore / Grindelwald, where you see them from when they were young teenagers up to when they're old, they were always on opposing sides of an argument over how the world should work while still having a love and respect for one another. But while Eraqus had that for Xehanort going by BbS and 3, I don't feel Xehanort had that for Eraqus? The way he talks about Eraqus in BbS is mostly with disdain that felt like it went beyond their difference of opinion.