A standard deviation could be set for price feed. A large amount of stake could be enabled for people to run node with slashing. A reputation mechanism and a data validation mechnaism also has to be there. Sort of like baker and endorser. (And anonymity should be forbid, it then also put a minor pressure from community to stay active and honest)
All the questions are good and I think Oracle network design comes close to protocol design. Incentivisation in XTZ could be a task and a very interesting point imo for people to run nodes.
