Setting up small writing school as auto-entrepreneur?

We have lived in France since 2005 and have 3 small boys. The boys and I have dual French and British nationality as my mother is French. My husband works and pays tax in the UK as a self-employed person. I worked part-time here for 3 years and am currently on conge parental until June 2012. We would like to set up a small writing school from one of our out-buildings running 5-day tutor-led courses. Initially we plan to run 3 or 4 courses next year over May, June and July. Do you know of any relevant grants we may qualify for to help with the cost of renovating the barn? The costs we have incurred to date have been put through my husband’s UK accounts.

How would I make the transition from a salaried position to auto-entrepreneur status? We want for the boys and myself to remain ‘in the system’. Is this as straight-forward with auto-entrepreneur status?

Am I obliged to return to my previous job at the end of my conge parental? If so, for how long? Is it possible to be salaried for another employer and have your own small business? If the business is set up in my husband’s name, can I be a salaried employee of the business? Or vice-versa? It is likely our business will be very seasonal - how do we pay the cotisations and charges for the remaining trimestres of the year? Can we apply to set up the business at the end of the first 3 months so that we can see whether the whole venture is viable first?