"...invention of the "imputed righteousness of Christ"
"Invention?"
That is funny.
Here is a brief survey of Catholic "inventors":
The Catholic Hermann Volk sees imputation as an essential aspect of justification since Christ's righteousness is "reckoned" to us (see his "Imputationsgerechtigkeit" in Lexikon für Theologie und Kirche [Freiburg: Herder, 1960])
Hans Küng writes that this "legal character is of fundamental signification for justification." Furthermore, as a forensic statement of the divine Judge, it involves "a declaration of justice, a court judgment, a nonreckoning of sins, and a reckoning of Christ's justice (imputation: Rom 4; Gal 3:6) through God" ("Justification and Sanctification According to the New Testament" in Christianity Divided: Protestant and Roman Catholic Theological Issues, ed. by D. Callahan, et al [New York: Sheed and Ward, 1961] 315).
Other Catholic theologians, such as Ricardo Franco, see the biblical term "justification" as refering primarily to God's judicial verdict of pardon and right-standing, whereby a new relationship is initiated between the person and God, and it therefore cannot be interpreted merely as a synonym for the infusion of grace (see his "Justification" in Sacramentum Mundi, volume 3 [New York: Herder and Herder, 1969], 239-241). Franco goes on explain this verdict as the forensic application of eschatological judgment to us now, in Christ, a judgment that is not based upon us already being inherently righteous, but that is antecedent to and creative of any growth in actual righteousness.
J.P. Kenny, writing in the Catholic Dictionary of Theology (London: Nelson, 1971), says regarding "justification,"
...[Paul] interchanges it at times with the phrase "to reckon as just" (Rom 4:3; Gal 3:6). When used of the end-events and set in opposition to condemnation (Rom 8:33; 1 Cor 4:4) it is clearly used in a forensic sense, and sometimes it has associated with it the Jewish law-court term: "in His sight" or "before Him" (Rom 3:20; Gal 3:11). Nouns describing the act or state of justification (Rom 5:16-18) are likewise forensic. The immediate sense of the term would thus be rather a declaring just and not a making just. (175)
Catholic scholars, such as [Joseph]Fitzmyer, have come to recognize that in the LXX dikaioun seems to have a declarative, forensic sense (see Fitzmeyer's summary of Pauline theology in The New Jerome Biblical Commentary; see also Michael Schmaus' Dogma, volume 6: Justification and the Last Things [Kansas City: Sheed and Ward, 1977]).
Catholic scholar George Tavard appreciatively wrote,
When [the Reformers] asserted imputed justification, they wished simply to deny a justice pertaining to man; they wished to make the Pelagian distortions of sanctification impossible, to kill at the roots the idolatrous desire to sanctify oneself through an accumulation of merits...We have nothing of our own: all comes from Christ. (Protestantism [New York, 1959] 27)
These are just some of more recent "inventors" and we haven't even touched on "inventors" such as Augustine, Anselm of Canterbury, and Thomas Aquinas.
Are you trying to prove my point? All the people you quote from are 20th century authors.
Fr. Fitzmeyer actually says that Paul uses "justify" in a transformative sense. You'd know this if you'd actually read his works instead of culling quotes from http://www.joelgarver.com/writ/theo/question.htm.
You can't seriously be suggesting that Thomas, Anselm, or Augustine would have any truck with the idea of the imputed righteousness of Christ. For starters, see the excerpts from De Spiritu et Littera which I gave above. As regards Thomas, you must be joking - his doctrine is followed very closely by Trent and Catholic theology.