I did mention I had tried setting the overflow:
> "I've set my text fields to display Unicode as well as have both vertical and horizontal Overflow. "
However I found the source of the problem. It was in the way Unity is packaging JSON files, which get assembled weirdly on build, so much so that a filepath in one's JSON parser can't access them. I moved it into Streaming Assets which are left alone on build, the parser could read the file and the text set itself fine after that.
Thank you for the response.