I think paladin can be done for high elves, as we do have "high elves shieldbearers" in the Paladin Order Hall, but I think it's not really required.
However... I think druid and shaman are a bit of a stretch, as the race itself never had any real connections to nature in the way that is required for druidism, and the same thing goes for shamanism.
Obviously, death knight should be an allowed class, even using the default starting zone, and yes, they should be mages as well, considering the amount of high elf magisters we see.