However, these variables are not always perfectly correlated. It is important to recognize cases where some or all of (1), (2), or (3) are easier to answer than the object level question. That is when trusting the expert consensus is a good idea.

Well I think all 3 need to be satisfied. But that only happens when the issue is non-controversial. In which case you can just look up the answer on Wikipedia.

If an issue is controversial, it's a pretty safe bet that one or both sides will (1) distort the issue to make the other side seem less reasonable; (2) exaggerate the extent to which supposed authorities agree with them; and/or (3) attempt to choose a class of supposed experts which is most favorable to their position.