Most character never mention their sexuality. What do they count as?

Well, they count as characters who don't mention their sexuality.

1: Bill from TLoU, as others have mentioned. Kaidan Alenko is another good example, in my opinion. One bad example, for me, is Mizhena in Baldur's Gate: Siege of Dragonspear, it's so awkward and out of place and so obviously tossed in for the sake of simply being there with little to no narrative purpose. Lena Oxton in Overwatch is also kinda strange as a concept, the characters sexuality literally has zero impact on gameplay or narrative as OW is a simple hero shooter with almost no depth. 

2: Interesting question, but it's kinda hard to know since it usually makes little sense for characters to blurt out their sexual preferences in most settings. If it's subtly done and well written, I'm all for it. But most such characters are fairly stereotyped and shallow and often seem placed out mostly for representations sake.

3: Not really, but it seems there's a ways to go before writers can create good LGBT characters since the above mentioned problems persist.

4: No, I'm straight.

I was a fan of Hannah and Rain in Fear Effect 2. The game was sold on their sexiness but they really did care for each other.

Fable/Dragon Age/Ass Effect all handled sexuality pretty tastefully I thought.

That would be fine.  It seems, however, that some people count characters who don't mention their sexuality as straight, then compare the ratio of alphabet characters against that.

I'd say Gay Tony Prince from GTA IV The Ballad of Gay Tony is a good representation because it doesn't feel as pandering. Despite being a stereotypical middle-aged gay guy, he shows some depth and development by how troubled he is. Despite that, I don't feel as there's enough representation of the LGBT community on videogames, particularly on protagonists and/or playable characters. Take Piers Nivans from Resident Evil 6, for example. In Resident Evil Revelations 2, he sends a letter to Claire where he subtly reveals a bit too much admiration for Chris, but he doesn't feel like revealing his true feelings to the player. Come to think of it, I could draw a weird comparison with real life by saying there are characters who are closeted towards the players due to the extreme toxicity from segments of the audience.

I think there are a handful of LGBT characters in games, but there's a lack of protagonists who are either gay or lesbian. One could argue that certain RPGs allow you to create your character and give him or her that kind of identity, but to my knowledge there's not a well known protagonist that can be considered gay. However, even if I would like for a gay protagonist, I feel it would unleash a lot of backlash from the community. Either he's pandering, or he's a gross stereotype, he's extremely bland, an insult for the LGBT community, etc. It's not like I'm desperate for some representation on gaming, but developers should push the envelope on the way they make the games.

1. Good example: any character that was LGBT by design as conceived.
Bad example: any character that was changed into LGBT despite being straight originally. This is the disease plaguing entertainment today.

2. There shouldn't be a fucking quota. There shouldn't be a checkbox for developers to add an LGBT character just for the sake of diversity. It should be organic. If the situation calls for it, good. If you're just adding one for a checklist, fuck off.

3. Representation for the sake of representation is bullshit. Just like battlefield 5's forced inclusion of one armed women on the front lines of world war 2 just for the sake of inclusion at the expense of logic and accuracy, it's freaking stupid. Add characters if they make sense, not to fulfill a quota.

100% this.