Sorry, two matters seem to be mixed up. First who is a 'real' Christian and secondly, what is the 'real presence'. Catholics rites consider all who are baptized in the name of the Father, Son and Holy Spirit as Christians.
In the coming Saturday night Easter vigil Protestants coming into the Church are considered Christians and not considered Catechumens (Unbaptized). Those that were Protestants receive the Sacraments of Reconciliation, Confirmation and the Eucharist but not Baptism because they are Christians.
In our Communion, you are asked to say Amen if believe you are receiving the actual body of Christ. If you can't truly say Amen, just don't go to receive. You are a Christian if you believe in Christ, you are a Catholic if you believe in the real presence. Go to the Easter vigil and see for yourself.