I emailed the Troll Lords about the High Elves and this is their reply:
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High Elves is that the only class they can have? What about multi classing?
No. High Elves can be any class or you can play the High Elf Class. If you chose to play one as a normal Elf (from the PHB) then you can multi-class as per the standard rules.
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The world is fairly gritty. It is just 60 or so years after the banishing of Unklar and the world is still recovering from the effects of 1000 years of winter. Most of the Kingdoms/countries are rather young there is great potential for rivalries and wars. Vestiages of Unklar's evil and government remain and have potential to manuipulate the newer powers.
The Elves are embittered or envious (depending upon whether they stayed during the Winter Dark and who left) and not generally trusted, the halflings are bitter and dwindling (they were hunted for sport). So there is racial tension as well as political.
On the religious front there are people who want Unklar back, new gods trying to establish themselves, and old gods trying to get reestablished.
Hope this helps a little. (wish I was as eloquent about Erde as Nightfall is about the Scarred Lands).