Do you have anything on how half-giants fit into the war and such? Like were they "created" during the war, did they exist before, what was their participation, etc?
They're a cross-breed. As such, they existed even before the war. Which side they fought on, if they fought, and how well they were accepted are all traits of the individual person / community.
They have no lands of their own per se, though in the giants land, there are a few communities of just half-giants and eneko. In human lands, they live with their families inter-mixed in the cities. (Think a family from Africa living in London... in 1547.)
Is necromancy, in general, deeply frowned upon in this world, or is it just the undead? Conversely, is it regarded as no different than the rest of magic, and only more deeply despised/feared in certain parts?
Mostly, it is dependent on use. I'll put this out in two points.
#1) If you cast Fear and Ray of Enfeeblement &al. then most people wouldn't even know the difference from enchantment for the first and transmutation for the second. Among those who know (decent Arcana), the problem is less, because they are educated enough to know what necromancy's range of abilities can / cannot do. Bear in mind, even SoD's aren't restricted to Necro, and Inflict spells and the like could just as easily be Conj/Evo.
#2) If, on the other hand, you start using powers that are blatantly abusable to nefarious ends, such as Contagion, or Animate, or use Summon Undead in the middle of a town (especially if you call something like an Allip), then people would be a bit more antsy.
That said, I just wrote up the bit on the
Blight Lands. Which would tell you a bit more about the kind of reaction you might get if people see you using Necro as per #2.
Just bear in mind, those people who were first banished were doing things like having Dread Wraiths under their control Spring Attack the schools, to convert the (non-warded) children into the Wraiths that would then go out to strike down the rest of the town. They were tried for unconscionable methods they used in the war for a reason. So don't think that you can't Zerg Rush a powerful enemy with weak undead just because that might come back on you badly despite victory, these guys were punished for going
way overboard.