Great images, I tried taking some stream shots and they weren't this nice. I need to try it when there aren't 1,000,000,000,000 (not enough room for zero's) mosquitos biting me, flying in my ears and mouth, and buzzing in front of the lens. Gotta love Northern Canada!! BTW our mosquitos are the size of small jetplanes.
Your images are great, #3 and 4 are my favs.
Insect bite is really a problem for shooting in the wild. I usually wear a long-sleeve t-shirt and on the sleeves and the collar, I spray the insect repellent in a bid to minimize bites. Our mosquites are mainly the culex and aedes species.
Annoyance caused by bitingmidges is also great in Hong Kong.
For floating water perpendicular to your camera, I think 1/2 of a second is good enough asthe silky nature of the floating water can be retained then. For water floating toward you, perhaps, 1-2 second(s) will do.It is my preference to retain traces of water motion in the images captured.