This looks interesting. I'm not sure I've necessarily got that much to add though but I'll see what comes out...
You're looking at utility, but this is with real people rather than a simulation, so I wonder how this will work.
Are they voting for more abstract things in which case will you ask the participants for their honest utility rating of the options in addition to their actual votes? Or are they voting for options that directly benefit them in a clearer way - e.g. option 1 means voters A, B and C get this amount of money/chocolate etc.
It will be interesting to see equilibria emerging from repeated elections, and which methods are more stable in that respect. There is obviously the question of how relevant this would be in the real world. National elections generally take place several years apart and a lot can change in between, and so voters wouldn't be able to apply game theory in the same way as they would with multiple elections close together under the same conditions. And also I imagine people in the study are more likely to be "clued up" than the average member of the public.
So that raises a question - with multiple elections, will it just be the same conditions each time just to see how the methods behave in these ideal conditions, or will certain variables change to make it more "realistic", or possibly you'd model both? Both would be interesting in their own ways.