Some of My Results (Individuals)
It is worth noting that for all scenarios less discordant than Zero-Sum, the average Agent was able to obtain positive Self-Gain.  So even in discordant environments, Agents can all gain by making rational choices. This demonstrates that rational ethical rules can still generate gain for all, even when encounters are discordant.  And it shows that the pursuit of Self-Gain is a valid ethical goal (though not the only goal).
This tendency toward Self-Gain influenced the effects of Reciprocity (a component of Altruism/Antagonism).  Because Agents were able to make gains, on average, Responsive Agents were willing to show Altruism (increase Other-Gain) in subsequent encounters.  The altruistic effects of Reciprocity were at their strongest in the Utopia scenario (where Self-Gain was essentially automatic) and decreased as the scenarios became more discordant (Self-Gain was harder to achieve).
Altruism had its greatest effect in the Neutral scenario (working mostly through Other-Gain), but became less important as the scenarios become more extreme.  In the Zero-Sum scenario, Altruism had no effect on any outcome.
In all scenarios, Basic Strategy determined Self-Gain.  The best strategy for Self-Gain was Best Row, though Minimize Loss and Best Cell also performed well.  Minimize Loss was better in discordant scenarios, while Best Cell was better in the concordant scenarios.  Assume Selfish also consistently performed above average, and tended perform best in the neutral scenarios.
The worst two strategies for Self-Gain were Most Surprise and Least Surprise.  Most Surprise was at its worse in discordant scenarios.  Least Surprise was at its worst in concordant scenarios.  Assume Death-Wish also was a consistently poor performer.
Assume Benevolence and Assume Persecution were mediocre Self-Gain performers, but had strengths in different scenarios.  Assume Benevolence was good in the concordant scenarios, but dysfunctional (negative Self-Gain) in the discordant scenarios.  In contrast, Assume Persecution was good in the discordant scenarios, but a poor performer in the concordant scenarios.
Reciprocity made a moderate contribution to Self-Gain in the most concordant scenarios, where strong positive feedback loops helped make better Self-Gain choices.  But even there, Basic Strategy still dominated the results.  The other component of Altruism, inherent Good/Bad Will, had no effect on Self-Gain.
In contrast, Other-Gain was most affected by the Altruism/Antagonism of Self-Agent.  Altruism had its greatest affect on Other-Gain in the neutral scenarios.  The components of Altruism, however, changed their respective importance as the scenarios became non-neutral.  Inherent Good/Bad Will was irrelevant in the Utopia, Comfortable, and Neutral scenarios.  Good-Will only became a substantial contributor toward Other-Gain in the Challenging scenario.  But it became a trivial factor in Zero-Sum, where any show of Altruism was ineffective.  In contrast, Reciprocity contributed most to Other-Gain in the Utopia, Comfortable, and Neutral scenarios, where positive feedback loops fostered Altruism.
Other-Gain was also influenced by Self-Gain, but only through the quality of the scenario.  Self-Gain and Other-Gain were independent of each other in the Neutral scenario.  As dictated by the Payoff Correlation, Other-Gain increased with Self-Gain in the Utopia and Comfortable scenarios, and decreased against Self-Gain in the Challenging and Zero-Sum scenarios.
Commonwealth was dominated by Self-Gain.  In general, an increase in Self-Gain also increased Commonwealth.  In almost all scenarios, the rank order of Basic Strategies was identical for both Self-Gain and Commonwealth.  This relationship broke down in the Zero-Sum scenario, where only zero Commonwealth was possible.
Increases in Commonwealth were moderately associated with Altruism, through increased Other-Gain.  Wherever Altruism was a major factor in Other-Gain, it also contributed to Commonwealth.  Altruism actually contributed more to Commonwealth in the discordant scenarios than in the concordant scenarios, but became irrelevant in the Zero-Sum scenario.
Commonwealth contributed most to Total Ethics in the concordant scenarios, and had less effect as scenarios became more discordant, becoming irrelevant at Zero-Sum.
Equality was dominated by Basic Strategy, but only for the more discordant scenarios.  Basic Strategy was trivial in the Comfortable scenario, and irrelevant (zero) in the Utopia scenario.  The Basic Strategy rank order for Equality changed little over the scenarios.  Only Assume Death-Wish and Assume Selfish changed their Equality ranking as the scenarios changed.  Assume Death-Wish generated more Inequality as the scenarios became more discordant.  In contrast, Assume Selfish generated more Equality as the scenarios became more discordant.
Least Surprise and Minimize Loss were the consistently best Basic Strategies for maximizing Equality.  Assume Persecution also performed well, as did Assume Selfish in the more discordant scenarios.  Most Surprise, Best Cell, and Assume Benevolence were the consistently worst strategies for Equality.
Both components of Altruism (Good/Bad Will and Reciprocity) had no effect on Equality.
Equality's contribution to Total Ethics was the inverse of Commonwealth.  Inequality was always zero, and thus irrelevant, in the Utopia scenario.  As the scenarios became more discordant, Equality grew in importance, until it became the sole determinant of Total Ethics in the Zero-Sum scenario.
Total Ethics
I am willing to entertain arguments to the contrary, but here I define Commonwealth (joint gain of Self-Agent and Other-Agent) and Equality (Agents having equal payoffs) as two independent dimensions of Total Ethics.  They represent two methods of ethical assessment.  Maximizing Commonwealth is the search for the greatest gain for all Agents, though these gains may be unequally distributed.  Maximizing Equality, however, seeks to equalize gains made by all Agents, even if this produces sub-optimal gains (or even losses).
Moreover, Commonwealth and Equality make unequal contributions to Total Ethics.  This is most starkly shown in the extreme Utopia and Zero-Sum scenarios.  In Utopia, all encounters generate equal results, making Equality irrelevant.  Commonwealth is the sole measure of Total Ethics.  In Zero-Sum, Commonwealth can only be zero, making it irrelevant.  Equality becomes the sole measure of Total Ethics.  In the Comfortable environment, there is much variation is Commonwealth, but little in Equality, making Commonwealth the more important measure.  In the Challenging environment, there is much variation in Equality, but little in Commonwealth, making Equality the more important measure.  In the Neutral environment, both contribute equally to Total Ethics.
So now we come to the question this web site was created to answer: which are the most ethical strategies?  In order, they are Minimize Loss, Best Row, and Assume Selfish, when accompanied by Altruism (either inherent Good Will, or a willingness to Reciprocate gain from a previous encounter).  These three Basic Strategies consistently showed a high Total Ethics across all scenarios.  It is worth noting that these basic Strategies also consistently showed high Self-Gain.  And which were the worst ethical strategies?  In order, they appear to be Most Surprise, Assume Benevolence, and Assume Death-Wish, when accompanied by Antagonism.  These strategies also showed consistently poor Self-Gain across all scenarios.
Two Basic Strategies produced divergent ethical results, depending on the environment.  In the Utopia or Comfortable scenarios, Best Cell performed ethically.  In environments where it is easy to make gains, and near-equal outcomes are the norm, Best Cell performed well (because it yielded high Self-Gain and Commonwealth).  But Best Cell performed poorly (in Total Ethics, Self-Gain, and Commonwealth) in the Zero-Sum and Challenging scenarios.  It was too naïve to obtain Self-Gain, and generated high Inequality.
Least Surprise had the opposite trend.  It performed well (high Equality and Total Ethics) in the Zero-Sum and Challenging scenarios.  Least Surprise could never obtain high Self-Gain (or Commonwealth), but it at least generated the most Equality.  This served it well, ethically, in the discordant scenarios.  But in the Comfortable and Utopia scenarios, Least Surprise fared poorly.  When Equality became unimportant, Least Surprise became less ethical.