Interesting ideas -- I can think of a few more. On the "smart = more moral" side:

• Smart people are more likely to be able to call on Kahneman's System 2 when necessary, which correlates with utilitarian judgments (see this paper by Joshua Greene et al.). Similarly, they're more likely to have the mental resources to resist their worst impulses, if they want to resist them.
• Note that some of your "smart = less moral" proposals concern a world in which some people are much smarter than others. If cognitive enhancement were widespread, we might get its moral benefits without the drawbacks of smart people suffering social stigmas of various kinds (your first two bullets in the second set).
• Being much smarter might include being much better at interpersonal skills, increasing empathy for others.
• Likewise, if there are morality network effects -- as in the tendency for well-organized societies to be less violent -- then a smarter overall population might be very much more moral.

On the "smart = less moral" side:

• If cognitive enhancement happens such that some people are much, much smarter than others, the temptation for the much smarter people to use their intelligence to take advantage of the less-smart people may be simply too great to resist. Presumably even very, very smart people will have their price.

By and large, I think I'd agree with you that it seems right that a smarter human population would be more moral, but it's by no means certain.