The premise here is that if Paul was not writing a theological tract for the ages — and everyone agrees he had no intention of doing that — then Romans must be understood within the circumstances of Paul's
ministry, as generated, as were his
other occasional letters, by a situation in his own
ministry or in a church that called out for his
apostolic attention.
If one really believes in justification by faith alone, differences over
other matters — the real presence in the Eucharist,
apostolic ministry, the indissolubility of marriage, the ordination of women, and on and on — make no difference.