Is that including historical background? If so, they have to receive a biased view as to how things actually transpired, what causes economic problems, etc.
The only way for them to not receive a biased view would be to actually see and know everything, in which case they would be godlike entities and that just makes the Original Position as worthwhile as asking "What would Jesus do?"
"What would Jesus do?" I like that analogy

I think its more of a tool/exercise to put a person or a group of people in a state to minimize there biases.
Rawls argument is usually used to justify some egalitarian meritocracy but Crispen Sartwell uses Rawls's argument to come to the conclusion that a group in the Original Position would choose anarchy. Not that I agree with him but I do find his argument beautiful.
Well, if you modify the variables, you can make the group come to just about any answer you want.