DPlot

Is there a way to have a plot that can be stored but occasionally updated with new (Excel) data, ............ or a template that saves extents, ranges, colors, text, etc to ease updating?

If you Edit>Paste Special and check the Link box, the link information will be preserved in a saved DPlot file. When you reopen the file it will offer to reestablish the link (which you'll want to do, otherwise that information will be gone if you re-save the file).

"or a template that saves extents, ranges, colors, text, etc to ease updating?"

File>Save Preferences and File>Get Preferences.