Starting a Software / Video Game Business in France

I am researching my options for starting a software business in France. I have started two companies and been self-employed in the US for the last decade. The main functions of the new business would include:

• Create, develop and publish software applications (primarily video games for mobile phones and tablets, but not necessarily exclusively).
• Provide consultation services for other software developers (this would be a secondary purpose).

Here are my questions:

1. What is the best legal structure for such a business? I envision being the sole owner/employee/operator initially, but it would be nice to have the flexibility to hire or contract others as I grow. Initially, it would be considerably cheaper and easier for me to work out of a home office - are there any limitations on that, and/or would it affect the choice of legal structure?
2. I also have questions regarding health insurance. Would starting such a business (and paying associated taxes) automatically entitle myself and my family (wife + 2 children) to health coverage in France? Are there minimum requirements on income/revenue that need to be maintained in order to keep coverage? For example, say I develop and publish several games, but am unable to turn a profit for the first X months / years, but continue to pursue the business - would we be at risk of losing our coverage? Or would I just need to make minimum payments to keep it?
3. My other area of questions is regarding the visa. I am a US citizen, and as far as I can tell, the best visa option I can find is the “Passeport Talent: Start-up entrepreneur.” There is a requirement of “proof of investment of at least € 30,000 in the planned start-up,” but it is unclear how I would provide proof of the investment prior to getting the visa, since the visa would be required to start the business - I can’t seem to find any details of what form this proof would take. There are similar “chicken and egg” questions I have in the accompanying required CERFA form (i.e., to apply for the visa, one is required to describe details of the business, but it doesn’t exist yet!). Do you have any thoughts or suggestions regarding the visa?

Thank you in advance!