Hi,
To answer your questions:
1. Real world units can be enabled in the layer properties. Right click layer > Properties > Display tab
2. There's a couple different workflows you can try
a. In the Symbology pane click the burger button > Match layer symbology to a style
Run this tool
b. Another option is to convert the symbology of your old preset layer to the unique value renderer. From there you can run the Apply Symbology From Layer geoprocessing tool on the new layer with the symbology from the old layer.
Hopefully one of these options will work well for your data. In a future release, one of the teams is working on a similar UI that will streamline this process a bit more.
thanks,
Andrew