Firstly, just to clear things up a bit, variations in wake turbulence strength between different aircraft can depend on a number of different factors - not just weight. For given speeds and atmospheric conditions, the foremost factor is wing loading (aircraft weight divided by wing area, or total lift divided by wing area for level, unaccelerated flight), followed by aircraft weight in general (which, of course, mostly plays into wing loading but can be a good indicator in its own right) and specific wing geometry. There are other defining components but, as I said before, the above is what you mainly look for in comparing different aircraft's wakes. So, out of the original poster's list of aircraft, you could get a rough idea of comparative wake turbulence strengths by looking at the respective aircraft's wing loading first and foremost. You can find such figures for some of those aircraft here
I think 'clean and slow' (pilots help me out) puts out the most wake behind any aircraft.
That is correct. It can seem counter-intuitive (especially the 'clean' part), but the very simple reason behind it can be found in the basic equation for induced drag and by considering the effects of slow flight on an aircraft's wing's coefficient of lift CL
Vortices have a life span of 1-2 minutes and a sink rate of approximately 500 fpm (?)
I have a feeling that vortex life span is a bit longer, but the sink rate is indeed about 300-500 fpm. The sink stabilizes around 500-900 feet below the generating aircraft.
The max take off weight of the 757 is usually around the 255,000 range, but apparently the highly efficient wing design (try getting one to descend quickly) has something to do with the vortice generation.
The 757's wing design isn't really considerably more efficient than others currently in the air and it doesn't play a major part in the 757's 'heavy' classification. Rather, the main culprit for the 757's relatively nasty wake is its relatively slow landing speed (for an aircraft its size). As I explained above, the slow speeds involved lead to a stronger wake during approach and landing (wake-critical periods of flight).
Hopefully this mess makes at least a little sense...