Well, you can't compare across vehicle lines because there' are too many variables. And you can't fairly compare two different engine families, because there are too many differences between the two. (For example, your Chrysler comparison compares a 3.3l to a 3.5l, which accounts for the fuel economy difference in itself.)

But on a single engine family, multiple valves will generally give better fuel economy because of the more efficient cylinder filling. Volumetric efficiency increases over two valves, which virtually dictates better fuel economy. However, nothing is absolute. (You may put on 4-valve heads with a cam that is far less fuel efficient and lose the benefit.) But it's pretty well understood that four valves = better FE. A good compromise between performance, FE, and emissions is the three valve arrangement, which MB and Ford have kind of settled on. Two valve is a little dated/cheap in my opinion.