Technically speaking, can someone who has been married to his first and only agnostic non-Christian wife for 6 years, and who converted to Orthodoxy a year after being married, become Catholic and participate in the Eucharist? If so, what would the process of conversion consist of normally?
Secondly, would having an unbaptized three-year-old son complicate matters at all?
If you are in a valid marriage, you have no impediment to the sacraments in the Catholic Church. You should discuss this with your local Catholic priest.
An Orthodox Christian is fully initiated. They are not considered converts. There is nothing to “do” to convert other than make a profession of faith. You would be a member of the corresponding Eastern Rite Catholic Church that corresponds to your Orthodox Church, if there is one. You are welcome to attend a Latin Rite Church, especially if no Eastern Rite Catholic Church is in your area.
Again, go talk to your local Catholic priest. If you are told you have to go through RCIA or other such nonsense, you need to contact the diocese. Some Catholics, particularly lay people running RCIA programs and answering parish phones, do not understand that Orthodox are fully initiated and do not “convert”.
No. Although you could certainly talk to the priest about preparing your son for baptism at the same time you enter full communion.
Based strictly on what you wrote, the answer is yes. You need only express your desire to the local Catholic pastor and be received into the Church–it’s a very simple process.
Secondly, no. It would not complicate matters, so long as you intend to raise that son Catholic. If you intend “not” to raise him Catholic, that might complicate matters because as a Catholic you would have an obligation to raise him that way. Of course, I’m presuming that you do intend to raise him Catholic. I’m writing it only because it’s part of the answer to your question.
The question though is that when you say converted to Orthodoxy, from what? That might complicate things, but it would not prevent you from becoming Catholic, it would only mean that there are other issues to be settled. Again, it would not prevent you.