Derivative Residence or FLR FP

[Jay1994]

Dear Good People,
I am an overstayer for 9 years. 3 years ago I married ( not legal in UK law) someone with an ILR (working on getting a British citizenship). We have a child who just had her British Passport issued. We all live together happily and my wife is a full time permanent support worker. I want to legalise my stay. I am torn between going for a derivative residence card or FLR FP. We are thinking of getting married and going for the spouse permit route later on. My wife works and we both live together taking care of our child I don't know which route will be successful for us.

Please guys I need help.

Thanks