Visa commercant

Hi Valerie, following on my introductory mail last week I have a few follow-up questions/comments please.

I understand that we require a visa commercant before we can register a business in France. My daughter and her husband, who are currently living on our property in Caux, France are in the country on a one year visitors visa. They will have to apply at the local Prefecture for this visa and submit a business and financial plan as part of the process. If the visa is awarded they can then get someone to help them register the business. All of this correct so far?
It is important that the business will be registered in both our names because my plan is to move to France in about 5 years time to work with them. So my questions are as follows:

1. At what stage do my wife and I apply for this visa - only when we want to move there?
2. How can we ensure that we are part of the business right from the start ( I will be providing the capital) from a structural point.
3. Can you give me a rough idea what is required to set up the business, including costs and investment required.
4. You mentioned it will be a lot easier to apply for the visa from outside of France. The challenge is that we don’t get back to South Africa anymore and now have resident permits in Switzerland - would it be possible to apply from Switzerland even though we hold South African passports?
5. Any other guidance will be greatly appreciated. The immediate priority is for my daughter and her husband to obtain the correct visa and set up the company - if we can achieve this it will be fantastic.
6. Do you know what else will be required for their visa application (other than the business and financial plan).

Thanks so much.
Christo