Alright, I have come to an understanding regarding Old Testament justification, thanks to St. Augustine, St. Thomas Aquinas and the Catholic Encyclopedia.
As far as I understand it, circuмcision remitted original sin and actual sin, but not the punishment due to sin. This was performed ex opere operantis based on faith in Christ to come.
If this can be shown to be wrong I will, of course, amend my position. If it is right, however, it in no way exonerates your heresy.