“since the books were clearly in question for many centuries”
No, they were not. Jerome lived in the 4th century. That was 12 centuries prior to Luther.
“Jerome tried to exclude them, was he a Protestant?”
Jerome did not do that. Jerome’s job was to prepare the Latin Vulgate translation. To prepare the Vulgate, he had to get the best Hebrew and Greek manuscripts. For some books he had Hebrew manuscripts - for others he had Greek Manuscripts. Some of the books in the Old Testament were originally written in Greek - but Jerome didn’t know this. What he did know is that some had Greek manuscripts and others had Hebrew manuscripts.
He expressed his concern that he only had Greek and not Hebrew manuscripts for some and expressed that concern to Pope Damasus. Damasus included them in the canon, where they remained for 12 centuries prior to Luther.
Let me put it another way. Jerome was closer to the founding of the City, than Luther was to Jerome.
Any way you try to slice it, there was a question about the authenticity, and inspiration about the books long before Luther showed up. To paraphrase Mr. Joel, Luther didn’t start the fire.
As you have already been shown, the fact is that while the apocrypha was generally accepted, debate and doubts about books continued right into Trent, and until then there was no infallible, indisputable canon for Luther to and some RCs to dissent from.
Meanwhile, the EOs and other Catholics have a different canon than Rome's but that never seems to be much of problem with RCs.
That said, i would say the wisdom of Solomon , if it was indeed written prior to the resurrection, seems to come close to being inspired of God, though apparently falsely attributed to Solomon.