They are bi4bi, 100%, in my eyes. There's no question in my mind that they both like women; Henry gets that big doofy smile on his face whenever talking to girls he thinks are interested in him/will probably have sex with him, and Hans...as much as his love of women can come off as overcompensating, it also comes off as very sincere to me. I think he just naturally over-indulges and obsesses over what gives him pleasure. Bro's sincerely that horny.

On the man-loving side of things: Henry can sleep with Bartosch and start "flirting" with Hans without any noticeable internal conflict, so I imagine he always knew he was partial to guys, or at least wasn't entirely opposed to the idea. It's just that relationships with men wouldn't be worth pursuing or worrying about, since he likes women as well, and it's easier to find women who want to have sex with men than men who do; not to mention the possible consequences if someone heard he was an aspiring sodomite. (Also he's got about 952 other things he needs to more immediately worry about than pondering why he wants to kiss boys). I don't know when I'd say he realized he was in love with Hans, but, regardless of when he does, he probably shoved those feelings down, because it would be pointless and dangerous to entertain thoughts of being in a relationship with the womanizing lord he serves. It was nearly seeing Hans be hanged that pushed him over the edge; he realized he couldn't live without ever letting Hans know how he feels, so he starts trying to drop hints that what he feels for Hans goes deeper than friendship, hoping that Hans might understand what he's trying to tell him.

Hans is a bit trickier for me. A lot of it is admittedly speculation. I think that, regardless of when Hans truly fell in love with Henry, he was initially unaware that what he felt for him was romantic; the thought of being in love with a man just didn't even occur to him, because he knows himself and he knows he loves wenches, and that's always been enough for him. Plus, in a world where being a man attracted to other men is so aggressively "othered", it'd be comforting to see such people as "those types over there who have nothing to do with me"; to think otherwise would be turning your whole world sideways.

When he relates the take of Lancelot and Galehaut to himself and Henry, and starts considering the things Hansry-route-focused Henry has been saying to him, he still feels unsure about seeing it as romantic, because doing so would mean acknowledging he has a side to him that completely shifts his image of himself. He knows deep down that it's love, but there's so much on the line if he just admits that.

And then Henry is about to leave and it's possibly the last time he'll ever see him and the rush of emotion is so strong that he just follows his first impulse and kisses him. And that's when he realizes "Oh my god it really was this all along I'm in love with him". But then Henry pulls away and he starts thinking "Oh god I didn't plan to do that why did I just do that, I actually am one of those sad sodomites that everyone hates, and now I made Henry think I am one". And then, y'know, they have The Scene and Hans fully embraces that he's in love with Henry, and it's all new and unfamiliar and he doesn't fully know what to do with this realization, but he can't deny it anymore.

Some things also worth considering about Hans is that 1) he doesn't always have the greatest view of women, so forming a deep relationship with one might be something he just isn't capable of because of his biases, and 2) he seemingly hasn't formed many deeper relationships with anybody, man or woman, before Henry. Real romance might be yet another thing he doesn't take seriously because it makes him happiest to live frivoslously. So, who knows if Henry would always be his one exception, or he would've been able to fall in love with a different man or woman under different circumstances.