I think we like sarcasm too much to ban it. Used correctly, it can make debates more fun and enjoyable.
As for my #5 about supporting claims with evidence, maybe that one should be re-phrased a bit so it says you have to support your claims with evidence IF someone challenges them.
I agree with what SummerRain suggested about dividing the guidelines up into one part that are absolute rules that the moderators will enforce and another part which is netiquette, i.e. debate forum norms that you're expected to agree to and follow, but it won't get you in trouble with the moderators if you mess up and accidentally do something which is discouraged by the netiquette.
As for my #5 about supporting claims with evidence, maybe that one should be re-phrased a bit so it says you have to support your claims with evidence IF someone challenges them.
I agree with what SummerRain suggested about dividing the guidelines up into one part that are absolute rules that the moderators will enforce and another part which is netiquette, i.e. debate forum norms that you're expected to agree to and follow, but it won't get you in trouble with the moderators if you mess up and accidentally do something which is discouraged by the netiquette.