Gwen Quest line

So there's lines of quests for gwen. I've already finshed the norn line of quests.

Am I'm going to be able to go thru the last missions beat it and then be able to back and finshed the last two (Aursa and vang) thru hm?

or so I have to beat all three before moving onto "Heart of the Shiverpeaks"?

You have to do all 3 before you can progress in story line.