I'd like to be encouraging about your project, and I hope it's very successful. As far as looking up, and commenting on, every use of the word "one" in scripture, I think it's good to remember that the Hebrews were ordinary humans, and "one" was an ordinary word to them. If you imagine what it would be like to look up every occurrence of "one" in Moby Dick, say, or War and Peace, I think you would conclude that it was a huge effort likely to bear only a very little fruit.
On your question, I know that Malachi never heard of the "Holy Trinity," had no conception of the Holy Spirit as a person, and had never in his life heard of "God the Son." So he couldn't possibly be arguing for or against any of those ideas. Just like the verse says, Malachi was saying, "We all have the same God, so we should all be true to each other and our religion."
Perhaps. I just want to be able to find where "one" is modified, and so far from what I've examined, when "one" is modified, the examples make this quite clear, using plural pronouns or giving an idea of plurality, as with "a cluster of grapes". One cluster is made up of many parts, and "grapes" is plural. So far I've not seen this when used with reference to God.
I know Malachi couldn't be arguing for or against the Trinity, but this is a problem for me because I don't think trinitarians mind ambiguity.
Hi Pseudo-Onkelos, it sounds like you're doing a great job. Personally I do not think Trinitarians can get anything useful out of Malachi 2:10 and I doubt they would attempt the line of argument you have suggested.
Thanks. I just want to have all the bases covered.