I would first recommend talking to your insurance company to find out if they cover bariatric surgery, and if they do, what all is required/covered. One thing I learned is that even at the same insurance company, the coverage and the requirements to qualify can vary widely. This is because most larger employers actually are "self-insured". This means the insurance company just administers the health plan and your employer is the one paying the bill. As a result, the insurance companies let the employers have wide latitude in what they will and won't cover and what the qualification requirements will be.
For example, I have United Healthcare. I was also on United Healthcare last year, but with a different employer. The bariatric programs are quite different in terms of what they required and what procedures they'll cover. Note that some insurance companies also have specific providers they recommend.
Once you clarify all that, check with your bariatric program/physician. The bariatric program I chose required a psyc eval, an upper GI scan, and three months of meetings with their dietitian, even if the insurance didn't require those things.