Can an auto-entrepreneur have only one customer?

My wife and I live in a building of 17 appartments. At the last Ass Gen we offered to do the weekly cleaning of the public areas, corridors, stairs etc. for and agreed fee, instead of the expensive an poor quality service provided by the existing cleaning firm. This was voted on and accepted by the other co-pros. The management company said that if we did this we would have to register as auto-entrepreneur’s and take out a Responsabilité Civile Professionnelle insurance policy. We have now done this and received our Identifiant Siret and our APE number Nettoyage courant des Batiments.

It has been agreed by the co- pros that our fee will be set at a level 50.00€ per week, which will allow us to pay the 21.3% Cotisation Social and the insurance policy fee and end up with a net sum of 35.00 € per week. We commenced operation 01/01/2011.

I have the following questions:

1. Do the owners of each apartment qualify as individual clients?
2. On the Declaration debut D’activite I did not tick the box in question No. 4 to request three years social charges exoneration from ACCRE, Should I have done so? If so, is now too late?
3. I did not tick the box in Question 8, as we live entirely on our UK State retirement pension and are below the UK and French income tax threshold, was this correct?