You seem to be using the level of unity in families you know as the standard for how unified the Church should be. But Christ has a higher standard for how unified His Church should be. He prays in John 17 that we would be one as He and the Father are one. So it seems to me that you are lowering Christ's standard for the degree of unity in His Church. Paul in 1 Cor 10 makes it very clear that there are to be no divisions among us. But what is a plurality of denominations if not divisions among us? Paul says that we must all agree, that we must all have the same mind and the same judgment. Your position, on the other hand, seems to 'water down' what Paul is saying, and settle for a lower standard of unity.
-A8
But what you are saying is that, unless we totally agree on everything, there is schism. I don’t agree. No one on the face of the earth right now agrees totally with you or me. No one. What we can agree on are the basic beliefs in Christ. There we can have unity.