Question 1: AIDA is a bad stress test. Prime95 is the real deal. And yes, a Haswell at 4.2/4.3 is normal to go at 70 with h100i. Haswell is damn hot. It easier to cool down a I7 4930k/4960x than a Haswell. Haswell does not require a big heatsink or over-the-top water cooler, it is not size what matters with Haswell. What matters is how fast the heat can be transferred out of the chip, not because of the sheer amount of heat generated, but because of the high thermal density.
No, Haswell is just that bad. A lot of Haswell chips wall at 4.5/4.6. It is just how much the chips can handle. Getting a Haswell chip to 4.6 is like getting a Sandy at 5 GHz. They are that rare. Few "gold" chips (like 1 in 10/20) Haswell chips get to 4.7/4.8 like few "golden" Sandy's get to 5.1.
As for that, I'm not sure. I've always known prime95 to produce a lot of heat. Oh and as for the overclocking to 4.6ghz, it is possible that the CPU is reaching the thermal limit and shutting off before reaching windows. Sorry I haven't been that great of a help.