I finally got around to extracting the maps from the high poly eye monster sculpt for the low poly version. I think everything turned out well, but the important lesson I learned was to add smoothing groups BEFORE exporting to sculpt. This is the reason my faces appear faceted. I did try to use smoothing groups after the maps were transferred, but I feel like it made it a little worse.
Original sculpt can be found here.
High poly model at about 37 million polygons, way too much, this was my first ever 3d sculpt: