Margrid the Sly or Master of Whispers?

I'm at the fork in the quest chain in nightfall. Which one is the least popular? Also do I have to join a party with another player to do the other missions or do I get access to the other later on?

You'll get the hero and access to their missions later on. I liked Magrid's quests and missions but a (second) Necromancer hero may be a better choice.

The choice between Magrid and Master of Whispers may be tied to the choice between Sosuke and Jinn earlier because after Jin Magrid is the only Ranger until Eye of the North and the ele heroes come in abundance and early in the game, so, for best 'completeness' of your heroes, Jin and Master of Whispers.

I used to do Master of Whispers ones first, as Amy said the Necro hero is generally more useful than ranger one. However I find Magrid's quests much more pleasant and easy (I have some hate for Drazgonur's master) so with mercenaries and few use of storyline heros I'm always doing those now.
So it's all on needing the hero or not.

Margrid the Sly, Dzagonur Bastion is a really crappy mission to do.

Magrid leads to 2 easy missions, Master of Whispers leads to 1 easy and 1 hardish mission. Many people find Dzagonour Bastion a hard mission to do, especially if you want the bonus from it. Although to get Protector of Elona title you will have to do it.

You can get both hero's however - once you complete the last mission in the game you will get transported to an area where you will be able to acquire a quest from the hero's you missed, which will allow you to acquire every hero from Nightfall (apart from Razah).

In the end the basic choice is - do you need a Ranger or Necro hero before you end Nightfall? Then choose either one and don't fret about which missions are easier or harder - read the guides, hints & tips on both the official and unofficial wiki's. I used the necro minion mancer & rit healer/spirit's split party method to get the bonus on Dzagonur Bastion, so it's not that bad/hard (it's just tricker than the other mission you get going with Magrid).

A necro hero is much better than a ranger hero.

Its my opinion, but i think ranger heroes (and ranger henchmen) are the worst.
Anything they can do, another class can do better.

The choice is up to yourself but,

I would go for Jurah (Master of Whispers ) reason is you can utilise Master a l

lot more in builds .
At the last Mission in Elona you will be able to collect all the heros that you missed along the way. so no need to worry in that respect

I'm not too concerned about getting the heroes I'm just wanting to do both missions for Protector of Elona. Wil I be able to do Dragonzurs later on?

Zero, yes, you can do the other missions later after you finish Nightfall and get the other hero. Or you can do the missions with another player that has the hero you're missing.

save Masters mission until after. The more options you have going into the bastion, the better. Even with the best build, positioning and awareness of what happens when makes the difference between masters and failing miserably.

Masters first would be my suggestion. You can always latch onto a group to do Dzagonur Bastion.

Ok now I have another question. How do I get my heroes to get other elite skills? I bought the skill packs and I still nee some elite skills. For example I need unyielding aura for dunkoro but I can't find the hero skill trainer that teaches It

U cant get Elite skills from Skill trainers.

U have to capture them with a Signet of Capture.
A Signet of Capture can be bought from most Skill trainers
Equip the Signet of Capture, and go kill the Boss that has the Elite skill u want.
Then in close proximity to the corpse of the dead Boss, use the SoC and select the Elite from the list of skills the Boss used.
If its an Elite skill for a Secondary profession, make sure your secondary profession matches the profession from the Elite skill u want.
An Elite skill gotten this way is then available to that character and all heroes.

One other method is, is to gather Balthazar faction via PvP matches.
Then with enough Balthazar Faction u can get skills and Elite skills from a Priest of Balthazar.
Skills gotten this way can be used by alll heroes but not (yet) by your character.
Your character can learn these skills by using skill tomes (for normal skills) or elite tomes (for elite skills).

If you've got the skill unlock packs all the skills should already be unlocked and thus available for hero usage. You won't need to obtain them from anywhere. UA is a Divine Favor skill; perhaps you were looking in one of the other attributes.

Yep...there are 4 different skill packs. Are you sure you bought all 4?