{Well, between Steven Stone and Lanette, things are actually innocuous. It’s true that Lanette does have a crush on Steven, but then again, it’s also true that half of Hoenn does. Her feelings for him are more like those childhood crushes one gets on celebrities, if anything.
It’s just a tad less serious for her because she actually has a professional relationship with him. As Hoenn’s storage system administrator, Lanette serves as a liaison between the admin network and the Hoenn League, which Steven, being the (former/current/it’s complicated) champion, is a prominent member of. Steven has mild decision-making powers, and Lanette has full control over the system’s relationship with the League, which long story short means the two of them sit in on meetings regarding important decisions to be made. Think of the Pokémon Association meetings in the GSC arc of PokéSpec, and you’ll have what I mean. (It’s just that Lanette doesn’t take as active a stance in those as Bill does.)
Additionally, as a prominent member of the tech industry, Lanette sometimes gets sent to conferences that Devon is a part of, both to serve as a liaison for the network (and what’s technically their actual employer, the Pokémon Cutting-Edge Technology Research Center) and the rest of the industry and to see what other prominent actors in it are doing. Sometimes, she’s even sent to more formal galas too, if someone/the Symposium sends an invite. (Bill is sent to similar events in Kanto/Johto; these are the “formal dos” he can’t really stand.) Meanwhile, as the heir to Devon Co, sometimes, Steven is dragged to these events on behalf of his father.
Which is to say they spend a lot of time crossing paths. Eventually, after a few times crossing paths and talking about how utterly delightful conferences, galas, and League meetings are, they decided that crossing paths in more relaxed settings was in order. Now and then, whenever Steven has a moment and Lanette isn’t getting sent to other regions on behalf of the network, they sit down to coffee. It’s perfectly platonic, and it mostly involves catching up and talking crap about half the League. Steven is apparently more into gossip than one would believe, for someone who spends much of his time shirking duties in favor of cave-diving.
As for Bill and Steven, that’s a little more complicated. They respect each other as experts in their respective fields (technology and general pokémon for Bill; steel-type pokémon, battling, and rocks for Steven), and actually, because they’re both avid collectors of one thing or another, they get along well. That whole thing about how they trade leads for rare pokémon and stones? Completely true. It’s just that they have less of a reason to meet up than Lanette does with Steven.
But Bill is a little jealous too. On the one hand, he has the same mild crush on Steven as Lanette has. He sees Steven as a fascinating person, a good-looking one at that, and, hey, the heir to a prominent tech company, so worth a conversation or few. So yes, he’s a little jealous that Lanette spends so much time with Steven. On the other hand, he’s also a little jealous of Steven for spending so much time with Lanette for a number of reasons, mostly having to do with how much attention Steven gets from Lanette.
Bill’s relationship with Lanette is a mite more complicated than just professional partners. They met essentially as kids, so they do see each other as childhood friends, even if by “as kids,” I mean “in college.” But not to give a character a needlessly angsty backstory, Lanette is quite literally the first human being Bill ever considered a close friend. Sure, he’s had friends before, but … let’s just say not a lot of his childhood friendships lasted, especially after his older sister took off for a pokémon journey when he was eight. Lanette, meanwhile, always had Brigette, and in any case, she’s generally better at socializing than Bill is. She was basically the one who took the first step and reached out to befriend him, and he never really forgot that.
So from Lanette, their relationship actually is platonic, even though she jokes frequently about The Phase. There is some truth to it, though. Literally everyone goes through a weird period where they think they have a crush on Bill, and that does indeed include Lanette. It’s just that the crush for her was still a mild one. And also still in the past tense. Otherwise, she considers herself a close friend and partner to Bill. She’s protective of him and will do what she can to make him happy, but it’s not in her mind romantic in nature. (An anon put it best, actually. She considers their relationship queerplatonic if anything.)
Bill, on the other hand, has this fierce need to preserve that relationship because he’s constantly astonished that it’s actually lasted this long. In some respects, he’s a little confused by it too. He sees Lanette as this beautiful, intelligent, absolutely amazing woman, and he does feel a sort of happiness whenever she walks into the room. It’s just that he’s not sure whether or not these feelings are actually romantic. Yes, he’s dated other people before, so he knows what romantic feelings look like. The problem lies in the fact that occasionally, he has feelings similar to those with Lanette, but he can’t tell if he’s actually feeling that or just a deep, unwavering loyalty to a friend and partner.
Either way, Bill ultimately tries to agree with Lanette on the subject of where they stand with each other, but he’s lying about the idea that it’s because he wants to discourage the other system admins from hooking up and making a dramatic mess of the network. It’s actually because he’s afraid that changing the status of his relationship with Lanette or otherwise making a move that is definitely romantic (when Lanette clearly wants a partnership out of this and when he’s not sure if he doesn’t want anything else) would be a terrible, relationship-destroying move.
Or in other words, Bill’s pretty sure “queerplatonic” fits them, but human interaction is just … really weird for him.
(Also, yes, Lanette is fully aware of all of this confusion.)}
The Pokédex According to Bill 