Really like this and have honestly been meaning to throw something of this sort together, I never really was a big fan of the restrictions on Darting/flashing, and relegating Two Weapon to basic only.
That being said- any reason this must be "two 1-handed weapons"? If you've got the hands, why not 2 2-handed, or 1 2-handed and 1 1-handed, or four weapons for that matter (though your wording doesn't seem to exclude MORE than 2 weapons), I don't see any real reason why the wording doesn't work as "armed with at least two weapons" or "have at least two weapons readied."
The only other things that stand out to me is that the passive "cannot be flanked" seems a little powerful for a second tier feat, maybe a lesser version of the same, something like "suffer no penalties from being flanked" so that Sneak Attack still goes off or you could, on the opposite side of things, do something like Sneak Attack resistance or the Two-Headed "only flanked by 3 or more" (yeah that's a little fiddly).
In fact, looking at these, not that I'm a nut about feats or anything, but I'd almost like to see them split into Sword & Board Basics (Guard weapons) and, lets say, Dual Wielding Basics (2+ weapons/double weapons), as right now the feats are a little back and forth on needing the Guard quality.
Great job so far, though