How do I start an auto entrepreneur business in France?

I have a lot of questions now that I am ready to start my business. From what I have gathered, the steps would be to:

• Trademark and check the name of the company and activity at INPI
• Register the company as an auto-entrepreneur (it is a service industry)
• Wait for my Siret number
• Once I have a Siret number I can open up a professional banking account

My questions:

1. First is the above steps correct? Should I go to INPI first or auto entrepreneur?
2. I have a CDII contract with a language school… how will my carte vitale or social charges be affected once I am an auto-entrepreneur? I plan to continue working with the language school as I build my business. The business is an intercultural communication training boutique where I give business English training (hopefully with the DIF accepted), coaching, and continuing education workshops.
3. I may need to pay people once in awhile (for example a caterer for a special event, or another specialist to help with a client). Can I use the CESU to pay for these services?
4. If I sell anything online, like a book or t-shirts, do I have to pay taxes on those as well?
5. Even though I am employed (barely with a CDI contract), am I still allowed to use the BGE and seek business advice? I have wrote up a business plan, etc., and I am working on making contracts, a brochure about the services, etc., so I am curious if they will still offer advice.
6. Is it customary to use non-disclosure agreement in France for coaching or business where highly personal information my be exchange?