AnD4D - The plugin is setup such that if you attempt to create a camera with the same name as a pre-existing one, then a new camera will not be created.
About the issue with not being able to unfollow destroyed objects, this is something I'll have to fix, but I'll set it up in such a way that destroyed objects are automatically unfollowed.
On the last issue, I've never noticed any jerkiness with any of the zoom features, however, I don't have it set up to use the lag value supplied for following, so I'll look into changing that. As for the bounding values, I'll explain that next, as this sounds related to both of your problems.
cazbah - It sounds like you're either mixing up your upper and lower bounds, or you're using the wrong scale. It must be understood that when zoomed in, the zoom value is going to be larger that when zoomed out. Second, the scale is such that the value you give acts as a multiplier on the base zoom value of 100%, so a value of 1 would set zom to 100%, while a value of 2 would set it to 200%, a value of 0.5 would make it 50%, etc. Thus, if you wanted to, say, zoom out no farther than 50% and zoom in no more than %200, you would set the lower and upper bounds to 0.5 and 2, respectively.
I realize I wasn't entirely clear in the descriptions for those parameters as to how it's laid out, and for that I apologize.
Let me know if you guys run into anymore troubles. I don't have an ETA on the next version as I've been incredibly busy with school lately, but I'll do my best to have it out in a timely manner.