The claim of an analogy regarding sacramental necessity between baptism and penance is made by the Council of Trent, the Catechism, the Holy Office Letter of 1949, etc.
No it's not (except maybe in the spurious 1949 letter ... haven't looked at it much in years). Trent explicitly teaches that the Sacrament of Confession, although similar to Baptism in that it results in a soul entering the state of justification, is very different from the Sacrament of Baptism. Your allegation that the Catechism teaches BoD does not mean that there's an equivalence being made, as there's no reference whatsoever in the Catechism to Confession whatsoever in those passages.