Certificate of Eligibility

Hi, I have a question regarding Certificate of Eligibility. My wife is half Japanese and half Filipino but her citizen is Japanese. Currently, we're living in Philippines and she's planning to go to Japan to work there. And as I talked one of your staff she said after registering our marriage I need to get the COE to be able to go to Japan. We also have one child, does that mean I need to COE for my self and for my child? Btw, our child already registered in the koseki tohon so it means he is recognize as Japanese right? Our plan is my wife will go to Japan first, then after our documents are legalize, we will follow her in Japan. Is it possible us to go to Japan, please tell me the requirements for my son when entering Japan and for me as a Filipino Husband.

Thank you very much in advance.

simple rule,
if your son is Japanese (Passport) than he can go to Japan anytime.
You need to apply CoE like anyone else.