I think there is a major difference between your Orthodox view and the Catholic view. While you think that the different outlooks, say on Original Sin, are mutually exclusive between the Roman and the Byzantine traditions, the Catholic stance is that they are different but complimentary understandings of the one same reality. The Catechism explains it this way:
1200 From the first community of Jerusalem until the parousia, it is the same Paschal mystery that the Churches of God, faithful to the apostolic faith, celebrate in every place. the mystery celebrated in the liturgy is one, but the forms of its celebration are diverse.
1201 The mystery of Christ is so unfathomably rich that it cannot be exhausted by its expression in any single liturgical tradition. the history of the blossoming and development of these rites witnesses to a remarkable complementarity. When the Churches lived their respective liturgical traditions in the communion of the faith and the sacraments of the faith, they enriched one another and grew in fidelity to Tradition and to the common mission of the whole Church.
1202 The diverse liturgical traditions have arisen by very reason of the Churchās mission. Churches of the same geographical and cultural area came to celebrate the mystery of Christ through particular expressions characterized by the culture: in the tradition of the ādeposit of faith,ā in liturgical symbolism, in the organization of fraternal communion, in the theological understanding of the mysteries, and in various forms of holiness. Through the liturgical life of a local church, Christ, the light and salvation of all peoples, is made manifest to the particular people and culture to which that Church is sent and in which she is rooted. the Church is catholic, capable of integrating into her unity, while purifying them, all the authentic riches of cultures.