Documentation please of the "numerous times in his later writings that he did consider them to be Scripture," and that the directive of his Pope to include them excluded Jerome's notes which excluded them or even some as Scripture (he also included the Epistle to the Laodiceans ), and that the Council of Rome excluded further debate, contrary to what CE and Catholic scholars state.
I don't intend to post a treatise on the subject in this setting, but I would be willing to bet that a google search of Apocrypha will provide significantly different results and authors than a search of deuterocanonical. That exercise will only prove that unbiased research in the context of sectarian disputes is a very rare commodity (your site included).
It should be noted that St. Jerome's belief was that only the original version of any Scripture was inerrant and in this context he pursued the Hebrew Old Testament as the most authentic. He did not contend, like Luther later did, that the lack of extant copies invalidated the deutercanonical books.
I am not at home so I don't have access to my personal library but I do have "numerous" citations, both directly from St. Jerome (Eusebius Hieronymus) and indirect by those referring to him. I am sure that your penchant for research will enable you to locate them if you have a desire to pursue unbiased research.
Peace be with you