Completing Personal Story with a Friend?
The personal stories are surprisingly linear. While your racial sympathy choices are different, when they both end the personal story will return to how it used to be.
You’ll both be able to play the same missions together – after that story – and get credit for it.
Since the story quests are instanced you can play together all the way. Just be on the same map, and your friend will still get an invite. After that just finish his quest.
As Keyce said, after the arc the stories converge again to the same quests until you have a choice again. My friend and I deliberately take different paths, so that we can see more story arcs =3
Thanks for the answers