For #1, I would expect to see green+purple fringing on an APS-C camera such as the 50D or 7D, even though I don't see it on my 5D2. That is because they are significantly higher magnification, equivalent to using a 1.4X TC.

As for #2, yes, 135's focus ring is also loose and makes a much different clanking sound than my other L lenses. I don't mind the clanking at all, but I would prefer more dampening for manual focus -- I suspect they had to leave it pretty loose in order to achieve maximum focus speed (which is incredibly fast).