Implications of auto-entrepreneur business paid via CESU in France?

I have a business as a personal fitness trainer and am registered as auto-entrepreneur in France. I never considered being paid in Chèque emploi service universel CESU because I don’t always work in the client’s home and I sometimes do group sessions (4 people max) so it wouldn’t really be service à la personne. But now a client has come to me wanting to pay in what I think are CESU prefinancé - it’s a booklet of checks with her husband’s name and a fixed amount. From what I understand I can not accept them as an auto-entrepreneur, but I can accept them as personal income. I would rather she pay me as an auto-entrepreneur so it goes towards my retirement, and because it’s simpler for me, but I understand she already got these free from her husband’s employer.

1. I am with the RAM and do not want to lose my maternity benefits. Will accepting them have any impact on my health coverage?
2. Do I have to switch to the Caisse Primaire D’Assurance Maladie (CPAM) to accept CESU?
3. Will accepting CESU automatically switch me to the CPAM?
4. If I do this will I lose the maternity benefits I have earned from paying into the Réunion des Assureurs Maladie (RAM) for the past 2 years?
5. Have any auto-entrepreneurs also accepted CESU as personal income?

This has also made me wonder if I should go ahead and apply for an agreement as a prof de sport à domicile so clients can pay me with CESU if they choose. Has anyone gone through the process? Web forums suggest it requires a lot of papers and takes a few months. I also hear not everyone gets it, what are the criteria?