What throws some people off is that you can have any amount of a copy of a single card within the limits of the Objective Set limits. You could have 6 Yodas in your deck if you wanted. Or 8 Lukes, if memory serves. You used to be able to have 6 Yodas - 2 of those sets got added to the restricted list so now you can only have 4.
But yep, you can have as many copies of a unique character as the deckbuilding rules and card pool permit. And 8 Lukes is perfectly legal, although probably not advisable in practice