1. Yes,
providing your doctor has confirmed that your current weight is a threat to your health, and has therefore ordered you to enroll in a program to treat a specific disease, whether obesity (a designated disease as of 2002), hypertension, heart disease, or high cholesterol, for example. You must have this in writing.
While you cannot deduct the obvious – such as the cost of diet foods (considered a personal expense), home exercise equipment, health club/gym/spa dues, nutritional supplements or any costs that are covered by insurance
https://blog.turbotax.intuit.com/deductions-and-credits/is-your-weight-loss-tax-deductible-4577/
2. Yes, deductible The IRS publication 502 is very good. https://www.irs.gov/taxtopics/tc502
3. Yes, except supplements and exercise equipment at home. Pillow no. See this link for some good information also. https://www.gobankingrates.com/taxes/medical-expenses-can-write-off/
4. Yes deductible
5. Yes, deductible
6. Yes, see IRS Chief Counsel Memorandum on this. https://www.irs.gov/pub/irs-wd/10-0017.pdf
7. You don't mention but mileage to and from the doctor visits are a medical expense also.
