The uniforms in general are identical so the only customisation is the 'head' apart from 1 (maybe 2) stormtrooper options. These generic heads are the same for both Rebel and Imperial. First off the actual character customisation comes in the form of generic heads and a few hair styles inc beards on the males. However I do think that some of the customisation is a departure away from Star Wars and I do think some has no place in this game. You could argue that the game itself, with the way Dice have recreated the look of Star Wars is 'fan service'.
In terms of any extras or bonuses that could be unlocked specifically for 'Star Wars' fans, there is nothing. The actual sound effects though are exactly what you would expect which makes the poor voices of the characters stand out even more. The original score is still as fantastic as ever but the new bits of score are noticeable and whilst these are nowhere near as good as the John Williams original, they are 'adequate'. The audio overall is great too but I do find the voices in particular rather jarring as they are obviously not the original cast - some do a better job than others and the dialogue itself is rather weak too. For a Star Wars fan (like myself too), there is a lot to like but that's mostly down to the visuals.