(1) I find a duck in the woods and get as close as I can without the bird getting too nervous. I select an ISO that will allow me to get a fast shutter speed (ISO 400 allowed for 1/1200 sec here) then raise up the camera to match where I think the duck is going to go when it flies away to check I wont be badly over or under exposed. When I find a happy medium, I start taking shots of the duck foraging for food. I get closer to the duck so as it's body language and low quacking says it's about to bolt....One more step and....Away she flies. At which time I follow the bird as best I can trying all the while to keep it in frame and comp and take four or five good shots hoping the auto focus gets a good lock.
(2) I don't use tripods for my nature stuff but instead rely on the OIS and my method of holding the 70-300 lens. I use my right hand to hold the camera while my left arm is up in front of me acting as a cradle for the lens.
(3) This was taken with a 70-300mm and I was at the 170mm mark, so yes your 70-200 would have got this shot with ease. Also my 70-300 is NOT a fast lens
Hope this helps