Just a few comments: I'd argue, if you go by the book, that what Thorin wants most is to reconquer his ancestral home in the Lonely Mountain - the Arkenstone being merely a means to that end.
Also, the "name for a corrupted elf" question is a bit over-simplified... not all corrupted elves automatically become orcs, and the origin of orcs might be the subject Tolkien himself had the most difficulty with, never solving the issue before his death. It seems at least probable that not all orcs are corrupted elves, but that at least some have been made from men.
Just a few comments: I'd argue, if you go by the book, that what Thorin wants most is to reconquer his ancestral home in the Lonely Mountain - the Arkenstone being merely a means to that end.
Also, the "name for a corrupted elf" question is a bit over-simplified... not all corrupted elves automatically become orcs, and the origin of orcs might be the subject Tolkien himself had the most difficulty with, never solving the issue before his death. It seems at least probable that not all orcs are corrupted elves, but that at least some have been made from men.