1. Our marriage will have be convalidated in order to be excepted by the church ( I did not get permission prior to marrying in the Presbyterian Church), is this correct?
2. Our son, since he is only 3; will they have to baptize him again?
3. Will we have to be full converts (marriage accepted and husband converted) before our daughter can be baptized?
As I mentioned, I was a baptized as an infant and received my first communion in the Catholic church. I was never confirmed though.
I definitely think you need to talk with the priest in order to get your questions answered. I am pretty sure that the baptism will be accepted for your son. I’m not sure about your other questions. Just ask the priest. Praying that all goes well! Welcome back to the Church!