There are no alternative refrigerants than can be added on top of/mixed with R-12.
Yes
Further production of it is. Existing stocks of R-12 were allowed to continue to be sold, and recovered and recycled R-12 can also be sold.
Freon for your cars air conditioner
Water even if made of 2 inflammable gases don't burn because to burn ( to release energy) making of bonds is needed .In case of water hydrogen and oxygen has already formed bonds so it cannot burn...