Wilson is ace, and grey-aro in the sense of "it happens very rarely", bi when he does get a romantic interest in someone. He wouldn't use those exact words to describe it because he's from a hundred years ago, but he's reasonably aware of the parameters because he's tested them by experiment.

In Sail he and Maxwell are in a decaying orbit together, and that is my favourite ship for him when it's done right, but he has a lot of other cute ships in the multiversal world of fanworks. (One of my best friends is a WXson shipper so I see plenty of that in particular.)

I also play Wilson as transgender, so he's got connections to the queer community of the era that way.

(But stealth, because you didn't have many other options back then if you wanted to live a normal life.)

Bastion is about as asexual as it's possible to be; I'm not sure if they're 100% aromantic, because that's harder to separate out from simply having emotions and (in the general sense of the word) relationships with other sapient beings. They haven't felt anything that was definitely romantic love so far, at least.

I do ship them a little with a few other canon characters, although the one semi-popular ship they have with Orisa doesn't do anything for me. This is more in the realm of imagination than something I'm particularly dedicated to though.

Aradia is pretty normative for her species, which means she's bi without a strong gender preference. I feel like people forget this element of Homestuck trolls a lot???

Alternia does HAVE trolls who only like one gender (although the only examples we've seen were gay, so it's entirely possible that there's no such thing as a straight troll) but it's seen as a more specific preference rather than a whole identity, and if there are terms for it they're so obscure that Karkat the romance nerd didn't know them.

But then there's the quadrant system; without getting into all of it, trolls are expected to find four romantic partners and only one of those relationships would be conventionally romantic by the audience's standards (although the one with all the hatesnogging could be fairly described as unconventionally romantic).

Aradia did have a quadrant filled with Sollux before she died but it wasn't clear to her friends which of the two more positive quadrants it was. I'm not sure myself. The whole being an anhedonic apathetic ghost thing didn't have a great effect on their relationship but it did help when Aradia got raised from the dead.

Cirava is also a normatively-bisexual troll teenager estranged from their friends by a near-death experience! They at least didn't actually die, although they came a bit close.

They didn't get to keep their close relationships from before The Incident and they worry that anyone new they get close to is just trying to take advantage of them, so that makes it difficult to find either friends or quadrantmates.

Wormwood is really difficult to describe because he's a plant-person. From one perspective he's effectively asexual, because he's not attracted to meaty humanoids, but what sex even is for him is extremely different from the meaty mammal version and he does actually seem to enjoy hayfever season based on some datamined quotes.

I suppose what would clarify things the most would be if he met an eligible plant-person from some other canon. This has not happened in RP but I know they're out there.

That's sexuality in a fairly strict sense though; romantically speaking I'm reasonably fond of pairing him off with WX-78. I could also see him with Walani but I usually treat them as BFFs rather than lovers. I don't see why he couldn't fall in love with someone made of meat or metal.

Not that it's happened before but that's from lack of opportunity more than anything. Before DST his only friends were regular plants.