can you really describe their relationship as queercoding?
I want my computer back so I can answer properly, please send help
Yeah, especially on Mika’s side. He hasn’t shown any interest in women, like, ever. Outside the anime/manga he appears only to talk about Yuu, blushing, getting yealous(like, really jealous, not like that bullshit that happened in the anime) There’s serapuchi, where you can barely ever find him doing anything apart from that. There’s two souls toward the truth, there’s, well, everything about Mika tbh. Actually, is there any proof that he could be straight at all? Why am I even answering this? Mika has maybe as much queercoding as Shion. Maybe even more(if it wasn’t for that kiss)
On Yuu’s side there’s, well, the game, lol, where he sees two girls almost naked and he’s like “?” instead of “!” and you could say he’s just oblivious but this kind of reminds me to how Sorey was portrayed. In the anime he blushes at the girls but in the manga this doesn’t happen(plus bisexuality exists), the touches with both Mika and Yoichi, his blushing, the fact that he spends most of his time thinking about his male best friend and that the demon took his form to control him… This may seem unimportant in a sense but, hah, it’s not like the author could do something better. Queercoding is subtle. The thing with it is: it’s valid until proven wrong. Which means, unless the author stops giving his relationship with Mika so many romantic tropes and starts makig him show actual romantic interest in a girl(say, Shinoa) it’s queercoding.
For example, notice that now that Mika is in the squad, he’s the first one to be by Yuu’s side when something happens to him. It may be small but it’s how queercoding is. Just remember korrasami (sorry if you didn’t watch avatar): after Bryke decided to make Korra end with Asami, around season 3, all the scenes Korra needed comfort, Asami was there. That’s kind of the place where the love interest is.
I’m obviously just giving you my opinion on this. It could change though. Shinoa has been in the place of the love interest a couple of times too (then again, Mika didn’t even have the chance).
To make it short, the author can’t make mikayuu canon(unless it’s in a very ambiguous way, or stating it himself, but with subtle words), or show they are gay explicitly. All he can do is send hints and not pair them with girls. The moment one of them dates a girl or really shows real interest in one, it becomes queerbaiting.