Infinite Stratos/WMG

Chifuyu gave away her ability to pilot to Ichika
Chifuyu used to be a great pilot, but we never see her getting in an IS, and Ichika has taken hers. Is it because she's an instructor? Does she have some mental block to prevent her from piloting? I think she made the choice to pass on her power to her brother, because he was her biggest weakness. What better way to protect her brother than to give him the power to protect himself?
 * As of the recent volumes Tabane has an extra IS core and she also hinted Chifuyu may still have her IS its just that the core is no longer present as Ichika is already using it, if the epilogue is to be believed Tabane will deliver the IS core to Chifuyu.

There was no hacker for the White Knight Incident
We are told in episode 10 by Ichika that in the White Knight Incident, missiles were fired from various nations at Japan by a hacker. However, Ichika might be an Unreliable Narrator who only knows the official story, when the truth is much darker. Faced with the threat of a next generation weapon and the fear that Japan Takes Over the World, the final decision is to just Nuke Em. When that plan fails, the nations save face by claiming they were hacked. Japan accepts the story officially, but only because they already proved they can win any war that someone else wants to start.
 * Doesn't really look like it from Chifuyu's hypothesis. She claims  did all of it For the Lulz.
 * Considering that this is the incident that turned the IS from a cool new military toy with an annoying flaw to THE future of armed warfare, I think it's obvious that set up both the missiles and White Knight to make the IS look good.
 * The Light Novel seems to confirm this; the incident happened juuust after  was ridiculous. And then it beats down enough enemy vehicles to invade a large country. Alone. Without any loss of actual enemy life.

8-bit is trolling us all softly
Maybe the director was beating us with the Obvious Stick all along. Maybe Ichi-man is TRYING to act all oblivious and clueless. Why? He means too much to all the girls, and they mean too much to him. And he knows that as clear as day. Therefore, it would absolutely shatter their hearts if one of them ended up (eventually) with Ichika. And he would feel terrible because all the people he loves are now heartbroken and in strife. And that day WILL come. WHAT A TWIST.
 * Except this wasn't made by Studio DEEN, but 8-bit.
 * Duly Noted.

Ichika is an XX Male
It would be a convenient explanation for 'his' ability to pilot an IS.

Ichika is a clone of Chifuyu
The reason why Ichika can pilot an I.S. is due to

Chifuyu is the White Knight
Tabane already lampshade this but further confirmation of Chifuyu's involvement in the case is still needed. Still there are various hints of Chifuyu being much more than a mere sports champion. That will also explain the last WMG as this will be a very good reason to clone her or make bussiness(German Intelligency sharing info with her about Ichika's location in exanche of a year of tutoring their soldiers, for example). Finally, the "White Knight" incident is close to the date when Tabane revealed the IS to the world and, at the time, Shinonono and Orimura families was still close to each other.
 * Still doesn't explain how Ichika came to be when he was already training with Houki. And Houki herself definitely remembers Ichika unless both of them somehow had their brains altered in some way.

The one's responsible for kidnapping Ichika is the nation who's representative was about to battle Chifuyu. Germany found out about it and decided to "cash in".
Think about it, that nation knew about Chifuyu's abilities, and therefore saw they had no hope of winning. The only thing that crossed their minds was to win by disqualification, and what better way to get Chifuyu disqualified is by kidnapping Ichika. Germany found out about it, and "offered" to help her find Ichika's location in exchange for her teaching their students. If this is true, may god have mercy on their souls, because Chifuyu will not.
 * This sounds way too cool to not be Canon.
 * The thing that's always bugged me for this is that the tournament took "my brother was kidnapped, I'm going to save him" as a forfeit. Although I suppose she could've been a bitch about it ("Fuck you all, I forfeit! I have to save my brother!") or maybe 'cuz it's illegal to use IS's for real combat.
 * Jossed.

Why Ichika Can Use IS Cores
As of episode 12, Tabane states outright that Ichika can use any core, that it wasn't intentional on her part, and she has no idea how it happened. Here's my theory: Tabane used the most Badass person she knew, Chifuyu Orimura, as the model for the advanced Powered Armor she was developing for the military. On crafting the core, she made a breakthrough that allows for all the "magic" (hammerspace, massive power reserves, etc) that the IS has, but it only worked when a living person wore it--Tabane tried it herself, and it worked fine, so she hammered out any errors and took it to her backers. That's where they found out that because Tabane's model was female, the cores only work for women, and no one could reverse engineer it enough for it to work with men. Maybe Tabane even tried building it from the ground up with a male model, but couldn't get it right (you really can't force genius you know). Which brings us to Ichika. His DNA is close enough to Chifuyu's that the core still works for him. I don't know how close, exactly, siblings usually are genetically--I know parents are 50% (obviously), but I'm not sure whether siblings are more or less. This also fits well with the "Ichika is Chifuyu's clone" theory. If the only difference is a couple chromosomes, then obviously he's close enough.

Summary: The IS cores only work for Chifuyu. Everyone else is determined as "close enough" merely by being female; Ichika, as her brother (or clone), is close enough on his own merits. And yes, this probably means Chifuyu's dad could use an IS too.

Charlotte Dunois and Charlotte from Puella Magi Madoka Magica are
It is stated in her bio that Madoka Charlotte loves cheese. Ms. Dunois, for her part, is French and therefore a Cheese Eating Surrender Monkeys...

Tabane is
Think about it, why would she create the I.S. in the first place anyways?

Silverio Gospel was not unmanned
First and most obvious, in the light novels it was manned by the American representative, Natasha Fairs. But in the anime, there's still the fact that the thing had a very obvious visual heads-up-display, which would obviously be completely redundant for a drone. Of course, that does mean that Ichika impaled her in the chest, but she could still get medical attention.

Ichika's IS will fall in love with him
From what episode 12 seems to show, Ichika's IS has some sort of female AI. This is a harem anime. Do the math.
 * Of course, the AI is the White Knight, and almost certainly his sister (or the ghost of his sister? Mental clone? Whatever). That doesn't invalidate anything, just pointing it out.