(1) Should an average person try to study medicine and statistics and find out the answers for themselves, or use an expert opinion?

I don't think any person will be successful at losing weight based on following the 10 minute advice of an expert and doctors frequently take less than 10 minutes for talking to a patient. It takes learning about food and healthy eating. The same is true for every significant medical issue. It never makes sense to try to outsource the knowledge completely.

I would support people getting information about their health from organizations like 23andMe.

That's no decision that get's to be made on it's own. It's a decision that's the result of a system either being restrictive and only allowing experts to diagnose or the system being more free.

There should be a system where the studies are not easily gamed by financial interests of pharmaceutical companies

The question is whether the political realities of current insiders having that much power allow for such a system. Is change possible as long as power get's concentrated on well-funded people at the top of the system?

Or are we better off if we simply allow new entities into the system and allow them to do whatever they want? Entities like 23andMe that we currently block?