Your Leadership affects the other characters around you, but doesn't affect you. Someone else's Leadership does affect you.

Your leadership gives everyone around you escalating bonuses that max out at:
  • Willpower +1
  • Body Building +1
  • Initiative +10
  • Damage +15%
  • Chance to hit +10%
  • Critical Chance +2%
  • Immune to Fear
  • Armour +10%
The Willpower bonus - again, for everyone around you, but not you - kicks in at Leadership 5.

The Independent Trait gives you +1 Willpower. This is independent (sorry) of any other Willpower effects, including someone else's Leadership. So if you are Independent, you have:
  • +1 Willpower with no Leader in sight
  • +1 Willpower when affected by someone else's Leadership 1-4
  • +2 Willpower when affected by someone else's Leadership 5 or better.
The Obedient Trait adds +1 Willpower to the effect someone else's Leadership has on you, but does nothing for you if no Leader is in sight. So if you are Obedient, you have:
  • no benefit to Willpower with no Leader in sight
  • +1 Willpower when affected by someone else's Leadership 1-4
  • +2 Willpower when affected by someone else's Leadership 5 or better.

Does that help?

Generally, I am finding the Divinity Wiki very helpful in working this stuff out.