None of them are gay or bisexual as far as the public are aware. I'm pretty sure that if they were bisexual, they'd be the kind of people to not hide it. Before I go on, the main point here is that most of this is down to their sense of humour. Having been a fan since 2005, watched/read most interviews they've done and met them twice, I can pretty confidently assure your that this is exactly the type of stuff they did for a laugh (not anymore... they've kind of grown up).
1. Frank and Gerard maintain it was just onstage flirting. They have discussed this in an interview, but I can't find it right now :( He basically said that the reason they did it was to put off any homophobes in the audience, but when they realised some of the audience was enjoying it a little bit too much they stopped. Gerard has said at a show before "listen up, all you racists, sexists, homophobes, and just plain assholes, we've got a message for you; Go the f**k home! We don't need you here, and we certainly don't want you here! Don't buy our music, don't buy our merch, and if you have our CD, break it!"
2. They were talking about Marc Webb who directed the Helena video (and some of their other videos). This is their tongue-in-cheek sense of humour, I'm pretty sure they weren't being serious. Even if they were, kissing a guy doesn't make you gay/bi.
3. That Pete and Mikey thing was something made up by fans. They're just good friends. Good friends often hug each other or have a laugh together... that doesn't make them attracted to each other.
4. If you watch Life on the Murder Scene, you'll see that Bert and Gerard actually kissed in front of cameras as a publicity stunt whilst playing truth or dare. As I said before, kissing a male does not make you gay/bi.
5. That's just a Gerard thing. He's said before that when he's onstage it's like being a different person and he just does spontaneous things. It doesn't mean it meant anything.
6. This was Frank joking. Frank and Bob wouldn't have met until 2003-2004 when he'd have been like 23/24, so I'm pretty sure he would have kissed somebody before that (especially since he met his wife during high school).
So overall, yes, they are all married. Yes, they do fool around a lot. No, that does not mean they're bisexual. Notice how none of this (bar the 2011 one) is particularly recent? 20-something year old guys are immature (believe me), back in the day they drank a lot, did some drugs, were probably experimenting and were doing a lot of it for show. Some people like to believe that they are bisexual, but this is their opinion and it's probably wrong. I'm pretty sure the guys wouldn't be the kind of people to be ashamed to admit to being bisexual; they would have told us if they were. I firmly believe they're not... so now you can make your own mind up.