C3C 1.22: is war weariness a general civ attribute for a human player or is it dependent on which civ(s) I'm at war with?
If I understand you correctly, it is dependent on which Civs you are at war with. So, for instance you can have so-and-so much War Weariness from Civ A, while you even get War Happiness from Civ B.
Is WW reset when I make peace with a civ?
No, it is not reset immediately. And while you don't suffer from it anymore the numbers are still there -- if you will -- behind the scenes. In the same vein, you can accumulate WW points when you are in a government that is immune to WW, like Monarchy. You just would not suffer from it.
If not, when, how and how fast is it reset?
I believe you are asking about this from the OP:
List of turns and wwp
Turn 0- 1 reduction by 8: 121, 113
Turn 2- 3 reduction by 7: 106, 99
Turn 4- 7 reduction by 6: 93, 87, 81, 75
Turn 8-10 reduction by 5: 70, 65, 60
Turn 11-15 reduction by 4: 56, 52, 48, 44, 40
Turn 16-19 reduction by 3: 37, 34, 31, 28
Turn 20-23 reduction by 2: 26, 24, 22, 20
Turn 24-43 reduction by 1: 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0