As far as #3 goes, everyone I have talked to has matched my experience - changing running form can take a lot of time. Think of the uncountably huge number of strides you have already taken in your current form - every one of these constitutes a reinforcement of current practice. Changing to be more of a mid/forefoot striker means that the your calves and balls of the feet are now getting the bulk of the impact, which for some people can have some (hopefully temporary) unfortunate side effects while you adapt.

For general approaches for changing your running to be less of a heel striker, you might pick up one of Ken Mierke's books (Evolution Running, for example), since he is an advocate of this form. If you have the time, money, and motivation you might look for a place that does video analysis of your running form to see if there is anything specific to you that might be changed to help. When I did this, I discovered that my upper body was bent forward at the waist much more than I thought, which put my hips farther back to balance, which in turn put my lower body weight back on my heels. Once I knew this I had my upper body become a bit more vertical which allowed my hips to come forward and I eventually came to land more on the balls of my feet and less on my heels.