WiK quest line.

Do you need to have eotn to start the quests?

Also, if this is so can I bring someone who has not started the quests into the last mission without doing the previous quests? they don't need to reward or anything, they just want to see the mission.

Yup, you need it to take part to Zinn's Trial.

Also having finished EoTN on your character is the only, mandatory, prerequisite to access the Keep, as you can't see Zinn's Trial otherwise.

You can bring people along only during the last one, but they won't get any credit for it.

http://wiki.guildwars.com/wiki/War_in_Kryta/Walkthrough

1.yes, you must own EotN, but you don't need to complete it.

2. You cannot bring anyone along who cannot access the quests on their own.

Thanks for the info.

Zinn's Task can be completed instead but either that or completion of the EoTN expansion is mandatory.

That's true for the first 3 quests where the party must be moved to a separate instance, but not for the last two ones. Bartholos will show up in the Keep if anyone in your party can do the B4LA quest. Unless it was fixed overnight, talking to him allows anyone to enter the quest, but you won't receive any credit for it if you haven't unlocked the quest yourself.

Everyone in the party needs access to the keep, though.

Completing EotN isn't mandatory. You can beat Prophecies and still do the WiK quest line. The only thing you need EotN for is for access to Vlox Falls and access to the EotN outpost. A runner can take you to Vlox Falls.

Like above, you still need to be able to access the Keep in general. So you still have to go through all the dialogues and such and beat either Prophecies or EotN. Otherwise, they cannot join without access to the Keep.

Chark will only appear if you have completed the Eye of the North expansion or if you have completed Zinn's Task.

So, you won't be able to see the Trial - and hence proceeding in the Dialogues - without either finishing EoTN or Zinn's Task, while you can see any other dialogue at the camp without ever finishing Prophecies, but will be stuck before Livia returns. So, without the Trial, you won't be able to access the Keep.

To gain access to the Keep, finishing EoTN is sufficient and necessary as it unlocks both WiK content AND the ability to watch the Trial, while Prophecies is not sufficient.

No finished EoTN -> No Keep -> No Quests