Though the fourth is the least Haiku-esque one (no caesura, or "turning point"), it is the one I like most in terms of reading enjoyment. I'm a great big fan of alliteration, and you, as I told you after you introduced me to your Soundcloud recordings, have not just a tendency for alliteration and darkness, but a knack for them, and the fourth mini-poem exemplifies that quite a bit.
The third is probably the best Haiku. And probably the best poem of the lot as well. Maybe it doesn't convey the same clear message as the fifth, and maybe it doesn't go for as sharp of a caesura as the first, but it has a good combination, and the imagery is the strongest.
Heavy, yet not too heavy. Short, but it feels larger on the inside.
And it is always a struggle to make a short piece such as this contain such weight, but this one succeeds.
As to the haiku in general, it is interesting to me how interesting haiku can be, to write, the focus of clarity and meaning it demands of you. Especially if you try to go for the syllabilic constraint, it forces your mind into a certain avenue. It is, like the best haiku, and your best haiku of the lot, bigger on the inside than on the outside.
To some degree, all poetry is such, but I feel the shorter and more constrained the form, the more true.