So I just wanted to share a few things you should know about the Eriador Scavenger hunt:
1) It is available to players of all levels however the objectives will only be around Eriador (and from the looks of it only in areas that are solo-able). It does not however give xp.
2) You can complete it even if you have already done the original version. And yes it will give a second set of some of the cosmetic pets, housing items and dyes.
3) Not every year has 3 quests per year. So no you are not missing anything if you only see one for a certain year.
4) The Eriador quests do not count towards the original deeds. Instead there is a new deed which requires you to complete all 22 quests which rewards you with 6x dyes and a white stag pet.
And I think that is it, if you have any questions please feel free to ask!
-Miri